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Full text of "Assessment of concrete masonry units containing aggregate replacements of waste glass and rubber tire particles"

ASSESSMENT OF CONCRETE MASONRY UNITS CONTAINING AGGREGATE 
REPLACEMENTS OF WASTE GLASS AND RUBBER TIRE PARTICLES 

by 

Jerry W. Isler 

B.S., University of Colorado Denver, 1984 



A thesis submitted to the 

University of Colorado Denver in partial fulfillment 

of the requirements for the degree of 

Master of Science 

Civil Engineering 

2012 



This thesis for the Master of Science degree by 

Jerry W. Isler 

has been approved by 



Dr. Frederick Rutz, Advisor 

Dr. Kevin Rens 

Dr. Rui Liu 



Date: 4-13-2012 



Isler, Jerry W. (M.S., Civil Engineering) 

Assessment of Concrete Masonry Units Containing Aggregate Replacements of Waste 

Glass and Rubber Tire Particles 

Thesis directed by Assistant Professor Dr. Frederick Rutz 

ABSTRACT 

Sustainable construction has become an interest in the engineering community and 
several standards have been developed to assess the environmental impact of new 
construction projects. Research has shown that it is possible to use recycled materials to 
replace some of the traditional mixture components in concrete products and produce a 
more sustainable building material. Two materials that are currently recycled and have the 
possibility of use in concrete applications are waste glass and rubber tire particles. 
Because concrete masonry units are an important and widely used building material it is of 
interest to determine if the recycled materials can be used to make a concrete block with 
similar properties as those made with stone aggregate. 

This paper examines the use of waste glass and rubber tire particles as a fine aggregate 
replacement for the mixture design of concrete masonry units. Typically masonry units are 
made in an automated manufacturing process that is different from other concrete 
production. The process consists of filling molds with plastic cementitious material and 
consolidating the material by rigorous vibration and direct pressure. The units are then 
quickly removed from the molds and transferred to the curing section of the production 
facility. Testing of trial mixtures can be done by evaluating small batch trials at a 



production block manufacturing facility, but often this is impractical and expensive. The 
concrete masonry units in this research were evaluated in the laboratory under conditions 
meant to replicate an automated manufacturing process. 

Concrete masonry units made with fine aggregate replacement consisting of waste glass 
and rubber tire particles were evaluated and compared to current engineering standards. 
Properties such as unit weight, compressive strength and absorption were evaluated. The 
visual and aesthetic characteristics of the block and any potential benefits or problems 
were reviewed. 



This abstract accurately represents the content of the candidate's thesis. I recommend its 
publication. 

Approved: Dr. Frederick Rutz 



ACKNOWLEDGMENT 

The research for this thesis was performed in the concrete testing laboratory at the 
University of Colorado at Denver. Because an unfunded research project can be a 
challenge to undertake, the author would like to thank the following companies for 
generously donating materials used in this project and encouraging research in a more 
sustainable future: Rocky Mountain Bottling Company for donating the waste glass 
material and Academy Sports Turf for supplying the rubber tire particles. 



I'd like to thank my advisors, Dr. Stephan Durham and Dr. Frederick Rutz for their 
assistance during the preparation of this thesis. I also would like to thank all the members 
of my committee for their participation and insights into this project. 



Finally, I wish to thank my parents, Dick and Jean Isler, and other family members for their 
kindness in supporting this thesis. All of their contributions, whether large or small, were 
greatly appreciated and will not be forgotten. 



TABLE OF CONTENTS 

Figures vii 

Tables viii 

Chapter 

1. Introduction 1 

2. Literature Review 3 

2.1 Concrete Masonry Construction 3 

2.2 Sustainable Concrete Masonry Practices 3 

2.3 Waste Glass Recycling 5 

2.4 Concrete Masonry Units Made With Waste Glass 6 

2.5 Concrete Made With Waste Glass 7 

2.6 Fresh Concrete Properties of Concrete Made With Waste Glass 7 

2.6.1 Unit Weight 7 

2.6.2 Slump 7 

2.6.3 Air Content 8 

2.7 Hardened Concrete Properties of Concrete Made With Waste Glass 8 

2.7.1 Compressive Strength 8 

2.7.2 Tensile and Flexural Strength 9 

2.7.3 Alkali-Silica Reaction 10 

2.7.4 Freeze-Thaw Durability 11 

2.8 Waste Tire Recycling 12 

2.9 Concrete Masonry Units Made With Rubber Tire Particles 14 

2.10 Concrete Made With Rubber Tire Particles 15 

2.11 Fresh Concrete Properties of Concrete Made With Rubber Tire Particles 16 

2.11.1 Unit Weight 16 

2.11.2 Slump 16 

2.11.3 Air Content 17 

2.12 Hardened Concrete Properties of Concrete Made With Rubber Tire Particles ...17 

2.12.1 Compressive Strength 17 

2.12.2 Flexural Strength 19 

2.12.3 Freeze-Thaw Durability 19 

2.12.4 Thermal Properties 19 

2.12.5 Potential Health Hazards 20 

3. Problem Statement 22 

4. Experimental Plan 24 

4.1 Laboratory Plan and Goals 24 

4.2 Testing Concrete Masonry Mixtures in the Laboratory 25 

4.3 Designing Concrete Masonry Unit Mixtures 27 

4.4 Materials 28 

4.5 Phase 1 - Determining Control Mixture Proportions and Calibrating 
Laboratory Equipment 28 

4.6 Phase 2 - Examination of Aggregate Replacement in CMU Mixtures 29 



4.7 Concrete Properties 29 

4.8 Viability As A Construction Material 30 

5. Results 32 

5.1 Phase 1 - Determining Mixture Proportions and Calibrating 

Laboratory Equipment 32 

5.2 Materials 32 

5.3 Gradation Test 35 

5.4 Dry Rodded Unit Weight 37 

5.5 Control Mixture Proportions 37 

5.6 Compaction 42 

5.7 Phase 1 Results 46 

5.8 Phase 2 - Effect of Aggregate Replacement with Recycled Materials 52 

6. Conclusions 69 

6.1 Conclusions and Recommendations 69 

6.2 Recommendations for Future Studies 71 

Appendix 

A Information on Materials Used in Mixture Designs 74 

A.1 Materials Used in Research 74 

B Results Data 80 

B.1 Phase 1 Results Data 80 

B.2 Phase 2 Results Data 87 

References 96 



VI 



FIGURES 
Figure 

2.1 U.S. Scrap Tire Disposition 2003 14 

5.1 Waste Glass 33 

5.2 Trash in Waste Glass 34 

5.3 Crumb Rubber 34 

5.4 Gradation of Fine Aggregates 36 

5.5 Gradation of Coarse Aggregates 37 

5.6 Water to Cement Ratio at Which Mixture Will Ball 40 

5.7 Squeeze Test 41 

5.8 Drop Hammer Compaction Equipment 43 

5.9 Collar for Mold 44 

5.10 7 Day Compressive Strength vs. Unit Weight 46 

5.11 Cubes Removed from Mold Immediately After Compaction 47 

5.12 Cube Produced - Top View 48 

5.13 7 Day and 28 Day Absorption 49 

5.14 Unit Weight of Trail Mixtures 50 

5.15 Compressive Strength vs. Water to Cement Ratio -Trial Mixtures 51 

5.16 Compressive Strength vs. Percent Cement - Trial Mixtures 52 

5.17 1 Day Unit Weight vs. Percent Fine Aggregate Replacement 55 

5.18 7 Day Unit Weight vs. Percent Fine Aggregate Replacement 56 

5.19 Absorption vs. Percent Fine Aggregate Replacement 57 

5.20 7 Day Strength vs. Percent Fine Aggregate Replacement 58 

5.21 7 Day Strength Decrease vs. Percent Fine Aggregate Replacement 59 

5.22 28 Day Strength vs. Percent Fine Aggregate Replacement 60 

5.23 28 Day Strength Decrease vs. Percent Fine Aggregate Replacement 61 

5.24 7 and 28 Day Strength Curves for Waste Glass Mixtures 64 

5.25 7 and 28 Day Strength Curves for Rubber Tire Particles Mixtures 65 

5.26 Photo of CMU Cube with Waste Glass - Top View 67 

5.27 Photo of CMU Cube with Rubber Tire Particles - Bottom View 68 

5.28 Photo of CMU Cube with Rubber Tire Particles - Side View 68 

A.1 Potential Alkali Reactivity Testing 78 

A.2 Fine Aggregate Gradation and Soundness Testing 79 

B.1 Trendline - 7 Day Compressive Strength vs. Unit Weight 82 

B.2 Trendline - 7 Day and 28 Day Absorption 83 

B.3 Trendline- Unit Weight of Trial Mixtures 84 

B.4 Trendline - Compressive Strength vs. Water to Cement Ratio - Trial Mixtures 86 

B.5 Trendline - Compressive Strength vs. Percent Cement - Trial Mixtures 87 

B.6 Trendline - 1 Day Unit Weight vs. Percent Aggregate Replacement 89 

B.7 Trendline - 7 Day Unit Weight vs. Percent Aggregate Replacement 90 

B.8 Trendline - Absorption vs. Percent Aggregate Replacement 92 

B.9 Trendline - 7 Day Compressive Strength vs. Percent Aggregate Replacement 93 

B.10 Trendline - 28 Day Compressive Strength vs. Percent Aggregate Replacement. ..95 



VII 



TABLES 

Table 

2.1 Chemical composition of waste glass 5 

2.2 Typical composition of manufactured tires by weight 13 

5.1 Gradation test of fine aggregates 35 

5.2 Gradation test of coarse aggregates 36 

5.3 Unit weight of aggregates 37 

5.4 Mixture proportions of trial control mixtures 41 

5.5 Moisture content of aggregates 42 

5.6 Mixture proportions of control mixture 52 

5.7 Proportions of mixtures containing waste glass 53 

5.8 Proportions of mixtures containing crumb rubber 53 

A.1 Concrete masonry mixture design materials 74 

A.2 Chemical composition of cement 75 

B.1 Data for 7 day compressive strength vs. unit weight 80 

B.2 Data for 7 day and 28 day absorption 82 

B.3 Data for unit weight of trial mixtures 84 

B.4 Data for compressive strength vs. water to cement ratio - trial mixtures 85 

B.5 Data for compressive strength vs. percent cement - trial mixtures 86 

B.6 Data for 1 day unit weight waste glass replacement 87 

B.7 Data for 1 day unit weight crumb rubber replacement 88 

B.8 Data for 7 day unit weight 89 

B.9 Data for absorption strength vs. percent aggregate replacement 91 

B.10 Data for 7 day compressive strength vs. percent aggregate replacement 92 

B.11 Data for 28 day compressive strength vs. percent aggregate replacement 94 



VIM 



1. Introduction 

Currently there is a growing awareness that humanity may be living in an unsustainable 
manner with respect to its usage of natural resources. Although the supply of natural 
resources is finite, the demand for raw materials has increased greatly in recent years. 
The growing demand for natural resources is thought to be the result of a number of 
causalities such as technological improvements that have made more products available to 
society, rising affluence levels in the developing world and the overall increase in the global 
population. Another concern about the use of natural resources is the potential generation 
of C0 2 emissions and their harmful effect on the environment. These concerns have led to 
a re-evaluation of how natural resources are used and call for the implementation of more 
sustainable practices that preserve resources and allow them to endure for the future. 

In response to these concerns, the engineering community has begun to develop programs 
and standards that address sustainable construction practices. The U.S. Green Building 
Council has developed the Leadership in Energy and Environmental Design (LEED) 
program that provides guidelines to certify that proposed construction projects use 
resources that meet metrics for more sustainable construction (U S Green Building Council 
201 1 ). The International Standards Organization has developed a number of standards to 
be used in environmental assessment methods (ISO 2012). Recently the Portland Cement 
Association (PCA 2009) has proposed several amendments to the International Building 
Code (International Code Council 2009) that consider sustainability. The amendments 
differentiate between a high performance building that uses sustainable construction 
practices and code requirements based upon minimum standards. Sustainability is an 



important emerging topic in the field of engineering. Buildings and construction activities 
worldwide consume 3 billion tons of raw materials or 40% of the total global use (Roodman 
and Lenssen 1995). Therefore the design and construction of buildings is an important 
area to examine in order to provide a more sustainable environment. One of the most 
frequently used materials in building construction is the concrete masonry unit because of 
its versatility and durability. Concrete blocks are made from cast concrete that is a mixture 
of various batch materials including fine and coarse aggregates, cement and water. 
Research on concrete mixtures has shown that it is possible to replace some of the 
traditional batch ingredients with other materials such as those collected from recycling 
processes. This feature of concrete mixtures presents a unique opportunity to use 
materials that otherwise might be placed in a landfill. 

Recycling involves the collecting and reprocessing of scrap materials into new, similar 
materials. If a material cannot be reprocessed into its original form, often new uses for the 
material are developed. Typically items that are collected for recycling include paper, 
plastics, glass, metals, tires, motor oil and many other items. Two materials that present 
possibilities for use in concrete block as an aggregate replacement are waste glass and 
rubber tire particles. Waste glass has similar characteristic to the fine and coarse 
aggregates traditionally used in concrete block while rubber tire particles are similar to 
polypropylene fibers used in concrete to control minor cracking. Because sustainability is 
an important topic in engineering and the mixture design of concrete block allows for the 
possible use of recycled materials, this thesis will examine the potential for waste glass 
and rubber tire particles to be used as an aggregate replacement in the mixture design of 
concrete masonry units. 



2. Literature Review 

2.1 Concrete Masonry Construction 

Concrete masonry is a widely used building material provided on a number of projects 
such as industrial buildings, schools, hospitals, and residential buildings. It is an appealing 
building material because of its aesthetic appearance, versatility, durability and fire 
resistance capabilities. Concrete masonry units are rectangular blocks made of cast 
concrete with hollow cores. They are produced in an automated manufacturing process 
that consists of batching mixture materials, placing the materials in a mold assembly and 
then transferring the units to a curing operation. Units are made with different textures and 
widths to meet job conditions, but have common lengths and heights to standardize 
construction practices. Concrete masonry wall assemblies are constructed by joining 
individual concrete blocks together with mortar joints. In architectural applications concrete 
masonry units can be used as veneer or partition walls. Structural applications consist of 
loadbearing members where reinforcing steel can be placed in the hollow cores of the 
block and grouted in place to give the member its required strength. 

2.2 Sustainable Concrete Masonry Practices 

The Merriam-Webster on-line dictionary defines sustainability as "a method of harvesting 
or using a resource so that the resource is not depleted or permanently damaged 
(Merriam-Webster 2010)." Although there are many ways to define and measure 
sustainability, one of the most widely used methods for determining sustainability of 
building construction is the Leadership in Energy and Environmental Design (LEED) 



program provided by the U.S. Green Building Council. LEED is defined as "an 
internationally recognized green building certification system, providing third-party 
verification that a building or community was designed and built using strategies aimed at 
improving performance across all metrics that matter most: energy savings, water 
efficiency, C0 2 emissions reduction, improved indoor environmental quality and 
stewardship of resources and sensitivity to their impacts" (U S Green Building Council 
201 1 ). The LEED program has developed several categories to define sustainable 
construction practices including: sustainable sites, water efficiency, energy and 
atmosphere, materials and resources, indoor environmental quality, location and linkages, 
awareness and education and innovation in design. 

The concrete masonry industry has attempted to understand how masonry practices can 
be more sustainable and promote known sustainable uses. Concrete masonry units are an 
energy efficient material with a high thermal mass that store heat or cold for release at later 
times. This storage capability allows the masonry to release energy when demand is not 
during peak conditions saving energy and operating costs for the building. Other 
sustainable masonry practices include examining the life-cycle cost and durability of 
masonry walls. One example of this is the on-going research to reduce moisture infiltration 
and provide proper drainage in masonry walls since moisture accumulation tends to reduce 
the longevity of a wall assembly. Construction practices that utilize new types of 
waterproofing or improved flashing techniques are currently being investigated. Finally, 
sustainable masonry practices include re-examining the materials used in concrete 
masonry. Materials that use less energy and eliminate the need for processing new raw 
materials are favored over other materials. New sustainable materials being considered 
include the use of new types of cements, fly ash, waste glass and other materials. 



2.3 Waste Glass Recycling 

The use of glass dates back for thousands of years and today covers a wide variety of 
products. Typical uses of glass include container glass such as bottles and jars, flat glass 
from which windows are made, specialized glass used in televisions and computer 
screens, insulation made from fiberglass and other applications. Glass is made of sand, 
calcium carbonate and limestone which are commonly found in nature. Shao et al. in their 
study of the use of waste glass in concrete give the chemical composition of soda lime 
glass and fly ash as shown in Table 2.1 (Shao et al. 2000). 

Table 2.1 Chemical composition of waste glass 



Chemical Composition Soda-lime 

glass 

Si0 2 72.8 

Al 2 3 1 .4 

Fe 2 3 

Si0 2 + AI2O3 +Fe 2 3 74.2 

CaO 4.9 

MgO 3.4 

S0 3 

K 2 0.3 

Na 2 16.3 

P2O5 

Ti0 2 

B 2 Q 3 10 



Although glass can be melted down and reformed into new containers, several difficulties 
with this process remain. Glass containers come in various colors and reuse of glass cullet 
involves separation of the waste stream into various colors. Production plants that make 
glass tend to be large centers located in a limited amount of locations throughout the 
county. Energy must be used to transport the waste glass from the collection source over 



a long distance to the production plant. These difficulties have led to the search for 
alternative applications of recycled glass such as using crushed glass in civil engineering 
projects. 

2.4 Concrete Masonry Units Made With Waste Glass 

Research into the use of waste glass in concrete masonry units is very limited. Meyer et 
al. examined the use of waste glass in four different mixture designs of concrete masonry 
units (Meyer et al. 2001). The batch mixtures were made at a local block manufacturing 
facility. The first mixture was a control mixture with no waste glass. The second mixture 
contained 10% fine aggregate replacement of waste glass that passed a #30 sieve. In the 
third mixture 1 0% of the cement was replaced with finely ground glass powder that passed 
a #400 sieve. Finally the fourth mixture contained 1 0% fine aggregate replacement waste 
glass that passed a #30 sieve and 1 0% cement replacement of finely ground glass powder 
passing a #400 sieve. A limit of the study was that only 10% of the aggregate was 
replaced because of concerns about a possible alkali-silica reaction. 

The research showed that the use of waste glass did not affect the strength of the units 
significantly. There was a 8.9% strength reduction in the mixture with the 10% fine 
aggregate replacement for the 28 day strength test. The alkali-silica reaction was found 
not to be a problem and could be controlled. Future testing of the fire resistance of this 
new product was recommended, but the researchers thought that this would not be an 
issue since the aggregate the waste glass replaced had a similar composition. One 
interesting result of the study was that the addition of waste glass increased the output of 
the machinery used to produce the masonry by 6% which could result in a cost savings for 
the block supplier. 



2.5 Concrete Made With Waste Glass 

Although the research on the use of waste glass in concrete masonry is limited, there is a 
greater body of work on its use in concrete. A summary of this research is contained 
below. 

2.6 Fresh Concrete Properties of Concrete Made With Waste Glass 

2.6.1 Unit Weight 

The unit weights of concrete mixtures that contain waste glass as an aggregate 
replacement tend to be slightly less than normal concrete mixtures. This has been 
confirmed by a number of studies. Ismail and Al-Hashmi used waste glass as a fine 
aggregate replacement in their study of various concrete mixtures. The fresh density of 
mixtures containing 10%, 15% and 20% waste glass had a decrease in the unit weight of 
the mixtures of 1 .28%, 1 .96% and 2.26% respectively. Their research used waste glass 
that had a specific gravity of 2.19 and fine aggregate with a specific gravity of 2.57. The 
difference in unit weight was attributed to the lower specific gravity of the waste glass 
which was 14.8% lower than the fine aggregated used in the research (Ismail and Al- 
Hashmi 2009). 

2.6.2 Slump 

The use of waste glass as an aggregate replacement tends to reduce the slump of a 
concrete mixture. As the amount of waste glass increases, the slump accordingly 
decreases and the mixture becomes less workable. When waste glass was used as a 
coarse aggregate replacement, Topcu and Canbaz found that the slump of their concrete 



mixture was 9.5 cm when no waste glass was used and 8 cm when 60% replacement was 
used (Topcu and Canbaz 2004). Park et al. found a more significant decrease in their 
study that used waste glass as a fine aggregate replacement. A mixture with no waste 
glass had a slump of 13 cm whereas a mixture with 70% replacement had a slump of 8 cm. 
The decrease in slump was thought to be because the waste glass had a very angular 
shape. The waste glass particles used in this study were slightly larger than the sand 
particles which may have affected the results. Still, Park et al. concluded that the decrease 
did not severely affect the workability of the mixture and this potential problem could be 
overcome with the use of admixtures (Park et al. 2004). 

2.6.3 Air Content 

Studies have found that the addition of waste glass to concrete mixtures results in higher 
air contents. Park et al. found that mixtures with 30%, 50% and 70 % of fine aggregate 
replacement with waste glass had an increase in air content of 12.2-21.6%, 23.71-30.4% 
and 30.6-41.4% respectively. The increase in air content may be the result of the irregular 
shape of the glass and its large surface area that trapped air when compared to traditional 
aggregates (Park et al. 2004). The study done by Topcu and Canbaz similarly concluded 
that the addition of waste glass decreased the air content of a concrete mixture (Topcu and 
Canbaz 2004). 

2.7 Hardened Concrete Properties of Concrete Made With Waste Glass 

2.7.1 Compressive Strength 

The use of waste glass in concrete tends to decrease the compressive strength of a 
mixture. As the amount of waste glass increases, the compressive strength decreases 



accordingly. Topcu and Canbaz studied the use of waste glass in concrete that had a size 
between 4 and 16 mm. The mixtures studied contained two sizes of coarse aggregates as 
well as fine aggregate or sand. The waste glass was used to replace a portion of the 
smaller sized coarse aggregate. They found that mixtures with 15%, 30%, 45% and 60% 
waste glass replacement rates decreased the compressive strength of the mixture by 8%, 
15%, 31% and 49% respectively when tested after 28 days (Topcu and Canbaz 2004). A 
study by Park et al. that replaced fine aggregate with waste glass showed a similar pattern 
but less of a decrease in strength. In the study waste glass with a size less than 5 mm was 
used. Mixtures with 30%, 50% and 70% showed a decrease in compressive strength of 
0.6%, 9.8% and 13.6% respectively when tested after 28 days. In order to offset the 
decrease in strength, a polymer was added to some mixtures containing waste glass and 
was found to increase strength (Park et al. 2004). 

Finely ground glass powder has been found to exhibit pozzolanic characteristics and 
increase the strength of concrete. Shao et al. performed a study that compared mixtures 
utilizing glass powder, fly ash and silica fume as replacement for cement. The 
replacement rate was 30% for each mineral additive considered and the results were 
compared to a control mixture. The study concluded that ground glass powder having a 
size finer than 38-um or passing a #400 sieve exhibited pozzolanic behavior in accordance 
with (ASTM C 618 1998) and compared favorably to the fly ash mixtures. The mixture with 
the glass powder had a higher early and later strength than the fly ash mixture (Shao et al. 
2000). 

2.7.2 Tensile and Flexural Strength 



Topcu and Canbaz found that the tensile strength of concrete decreased as the amount of 
waste glass increased in a mixture. The tensile strength decreased 37 % for a coarse 
aggregate replacement of 60% waste glass (Topcu and Canbaz 2004). As mentioned 
above, the waste glass replacement rate for the study was for the smaller coarse 
aggregate used only not the total coarse aggregate used in the mixture. Park et al. 
reported that waste glass resulted in a decrease of 5% in tensile strength for a 30% fine 
aggregate replacement (Park et al. 2004). The flexural strength tests from Topcu and 
Canbaz's research demonstrated inconsistent results, but generally the flexural strength 
decreased as the amount of added waste glass increased (Topcu and Canbaz 2004). 
Park et al. showed that the flexural strength decreased by 3.2% with a replacement rate of 
30% and 1 1.3% with a replacement rate of 50% (Park et al. 2004). 

2.7.3 Alkali-Silica Reaction 

Early research into concrete made with waste glass found that the concrete expanded and 
cracked. Several studies have reported that the expansion of mixtures made with waste 
glass as an aggregate are the result of an alkali-silica reaction (ASR). ASR is a reaction in 
which concrete mixtures containing certain rocks used as an aggregate react with alkalis in 
cement paste to form an expansive gel that cracks the concrete (Shi 2009). 

In typical concrete production ASR can occur in mixtures made with certain siliceous rocks 
and minerals such as opaline chert, strained quartz and acidic volcanic glass according to 
the guidelines of ACI Committee 1 1 6 (Meyer et al. 2001 ). The formation of ASR gel takes 
years to develop and it is difficult to predict when it will occur. Waste glass contains a high 
amount of silica and studies have reported this to be the cause for the generation of ASR 



10 



in mixtures containing waste glass. Still there is much unknown about why mixtures made 
with waste glass exhibit effects similar to ASR and how to mitigate its effect. 

Research into limiting the potential for an alkali-silica reaction caused by waste glass have 
employed traditional mitigation techniques for concrete aggregates that exhibit the potential 
for ASR. These include using low alkaline cement, limiting the amount of material with 
potential for an alkali-silica reaction and adding very fine siliceous materials such as fly 
ash, silica fume or metakaolin (Lee et al. 2007). 

As mentioned above waste glass ground into a fine powder has been found to exhibit 
pozzolanic properties. Several research studies have indicated that the use of finely 
ground glass powder reduces the effect of ASR. Shao et al. performed a study that 
examined mixtures with glass powder and compared them to a control mixture. The 
mixtures with glass powder reduced the expansion of a sample to half of that of the control 
mixture when tested in accordance with (ASTM C 1260 1994) and were well within 
acceptable limits (Shao et al. 2000). It is theorized that the higher surface area of the fine 
glass powder may favor a rapid pozzolanic rate over a slower ASR rate during hydration of 
the cement products. 

2.7.4 Freeze-Thaw Durability 

Research into the freeze-thaw durability of concrete by Polley et al. indicates that the 
durability of mixtures containing an optimized amount of waste glass are acceptable 
though slightly poorer than normal concrete mixtures with a low water to cement ratio 
(Polley et al. 1 998). Testing of concrete samples to determine their durability stiffness was 



11 



done per (ASTM C 666 1997). Generally, mixtures with fine aggregate replacement 
performed better than mixtures that contained coarse and fine aggregate replacement. In 
the study several mixtures containing various amounts of waste glass were made and 
compared to a control mixture. Results of the study showed that the control mixtures 
demonstrated a stiffness drop of 4-7% within 10 cycles followed by little reduction of 
stiffness throughout the rest of the test. Mixtures with fine aggregate replacement of waste 
glass showed a drop of 5.5 % after 10 cycles followed by a drop of 2% after 600 cycles for 
mixtures with 20% replacement. Field testing of sidewalk pavement using waste glass was 
observed during three winters in Wisconsin. The test sections showed excellent resistance 
to freeze-thaw action. A small portion of the cement paste eroded from the top surface 
during the test, but the glass aggregate was well embedded in the concrete (Polley et al. 
1998). 

2.8 Waste Tire Recycling 

In 2007 the Rubber Manufacturer's Association reported that 89.3% of scrap tires were 
used in various manners. The total volume of waste tires used in the United States was 
41 05.8 thousand tons of tires. This represents a 1 3.5% increase in the amount of tires 
used in 2005. Stockpiles of existing waste tires have been reduced by 87% since 1990, 
but 128 million tires are still held across the country (Rubber Manufacturers Association, 
Scrap Tire Markets 2009). 

Tires are made of natural and synthetic rubber and often contain steel or fiber cords. The 
material properties of rubber tires are shown in Table 2.2 



12 



As discussed in Section 4, the focus of this thesis will be on fine aggregate replacement in 
concrete masonry units. Rubber tire particles are available in a number of different sizes 
and shapes, but crumb rubber most closely resembles the fine aggregate of sand. 
Siddique and Naik in their overview of concrete containing scrap tire rubber state that 
crumb rubber consists of particles ranging in size from a No. 4 sieve to less than a No. 200 
sieve (Siddique and Naik 2004). 



Table 2.2 Typical composition of manufactured tires by weight 

(Rubber Manufacturer's Association, Scrap Tire Characteristics 2012) 



Composition (wt.%) 


Passenger 
Tire 


Truck Tire 


Natural rubber 


14 


27 


Synthetic rubber 


27 


14 


Carbon black 


28 


28 


Steel 


14-15 


14-15 


Fabric, filler, accelerators and 


16-17 


16-17 


antiozonants, etc. 







A number of uses for scrap tires have been developed and are shown in Figure 2.1 . 
Siddique and Naik state that while many uses of tires are technically feasible, not all of 
them are economically attractive (Siddique and Naik 2004). 



13 



Electric Arc .Export, 3.1 

Furnaces, 0.2 



Misc./ 

Agriculture 

1.7 



Unknown, 10.3 



Cut/Punched/. 
Stamped, 2.0 




Ground 
Rubber, 9.7 



Figure 2.1 U.S. Scrap Tire Disposition 2003 

(Rubber Manufacturer's Association, Toward a Cleaner Environment 2004) 



2.9 Concrete Masonry Units Made With Rubber Tire Particles 

A review of the literature on the use of rubber tire particles in concrete masonry units 
(CMU) reveals that there has been very little research on its usage. Richard Frankowski 
has a United States patent for CMU made with crumb rubber (Frankowski 1995). In the 
patent, the CMU contained 100 parts of portland cement, 100 to 700 parts lightweight 
aggregate, 1 to 30 parts crumb rubber, 10 to 30 parts water and some admixtures. The 



14 



proportions in the mixture were determined by weight. The patent claims that the CMU 
made with crumb rubber had an improved crack resistance, heat conductivity resistance, 
noise reduction, and shock wave absorption capability when compared to typical 
lightweight units. The patent goes on to claim that the addition of crumb rubber to CMU 
will result in greater mildew resistance because of porosity reduction, the units will be 
lighter, the permeability of the units will be reduced and there will be less susceptibility to 
handling damage during installation when compared to typical units. The compressive 
strength of the CMU made with crumb rubber was less than a typical unit. 

Cairns et al. studied the use of recycled tires in concrete masonry. Their research 
examined replacement rates of 10%, 25% and 50% and compared these mixtures to a 
control mixture that had a water to cement ratio of 0.87. The control mixture consisted of 
two sizes of coarse aggregate, 6 mm and 10 mm. The rubber chips replaced only the 
largest size of coarse aggregate used in the control mixture. They found that the 
compressive strength of the units tested after 28 days decreased as the amount of rubber 
increased. For replacement rates of 1 0%, the strength actually increased by 22%, but for 
replacement of 25% and 50% the compressive strength decreased by 23%, and 41% 
respectively. Cairns also examined the use of rubber chips coated with cement paste and 
found that this slightly improved the compressive strength of the mixtures (Cairns et al. 
2004). 

2.10 Concrete Made With Rubber Tire Particles 



15 



Although there has been very little research on the use of rubber tire particles in concrete 
block, more research on its usage in concrete has been performed. A review of the 
literature on its usage in concrete is contained below. 

2.11 Fresh Concrete Properties of Concrete Made With Rubber Tire Particles 

2.11.1 Unit Weight 

The specific gravity of rubber tire particles is much less than that of typical normal weight 
aggregates used in concrete. Sukontasukkul in his study of crumb rubber used in precast 
panels stated that the average bulk specific gravity of the crumb rubber was 0.96 
compared to that of 2.43 for fine aggregate and 2.68 for coarse aggregate used in his 
research. This difference in the specific gravity causes mixtures with crumb rubber to have 
a lower unit weight than normal mixtures. Another factor that decreases the unit weight of 
mixtures with rubber tire particles is that they tend to have higher air contents 
(Sukontasukkul 2009). Khatib and Bayomy found that the unit weight decreases as the 
amount of rubber added increases. A mixture with no rubber particles weighed 2.4 kg/m 3 
while a mixture with 50% replacement of total aggregate volume weighed 1 .8 kg/m 3 (Khatib 
and Bayomy 1999). 

2.11.2 Slump 

In examining the workability of concrete mixtures with rubber tire particles, Khatib and 
Bayomy found that the slump of the concrete decreased as the amount of rubber particles 
increased. They investigated three categories of mixtures with different amounts of rubber 
tire particle replacement rates. The first category was made with crumb rubber to replace 



16 



a portion of the fine aggregate. The second category contained rubber chips to replace a 
portion of the coarse aggregate and the third was a combination of crumb rubber and chips 
to replace both fine and coarse aggregates. Their findings showed that when rubber 
particles were used to replace 40% of the total aggregate volume content, the slump for 
the mixtures with rubber chips was near zero and the mixture could not be worked by hand 
mixing. The mixture with only crumb rubber was much more workable than the other two 
mixtures (Khatib and Bayomy 1999). 

2.11.3 Air Content 

Several studies have found that the addition of rubber tire particles to concrete results in 
higher air content. Khatib and Bayomy found that as the amount of rubber tire particles 
increase the air content of the mixture increased (Khatib and Bayomy 1999). Conclusions 
of the study have been confirmed by Fedroff et al. who found higher air contents in 
mixtures containing crumb rubber than the control mixtures even without the use of an air- 
entraining admixture. The researchers thought that the higher rubber contents may be due 
entrapped air on the surface of the rubber particles due to their texture and non-polar 
nature (Federoff et al. 1996). 

2.12 Hardened Concrete Properties of Concrete Made With Rubber Tire Particles 

2.12.1 Compressive Strength 

Ghaly and Cahill studied the effect of rubber tire particles on the compressive strength of 
concrete mixtures. In their study mixtures with water to cement ratios of 0.47, 0.54 and 
0.61 were studied. The research program consisted of preparing 180 concrete cubes that 
were 2 in. x 2 in. x 2 in. Crumb rubber was used to replace the fine aggregate of the 



17 



mixture. Replacement rates were a percentage of the total volume mixture. For example a 
replacement rate of 5% represents 5%of the total volume mixture, not just a percentage of 
the fine aggregate. Strength testing was performed at 1, 7, 14, 21 and 28 days. They 
found that the strength of a mixture with rubber tire particles was less than that of 
conventional mixture and that the strength decreased as the amount of rubber particles 
used increased. The results of their study for a water to cement ratio of 0.54 and 
replacement rates of 5%, 1 0% and 1 5% showed a decrease in strength of 21 .7%, 48% and 
59.7% when measured at 28 days (Ghaly and Cahill 2005). The loss in strength from 
using rubber tire particles in concrete mixtures has been confirmed by several other 
studies such as the one performed by Khatib and Bayomy. In their research, a control 
mixture with a design strength of 5000 psi was use d. Crumb rubber was used to replace 
the fine aggregate in the mixture designs and replacement rates were by total aggregate 
volume. For replacement rates of 5%, 10% and 15 %, the study found a corresponding 
reduction in strength of approximately 26.3%, 36.8% and 42.1% when compared to the 
control mixture. In this study failure of the specimens was a ductile failure that had large 
amounts of strain before final fracture (Khatib and Bayomy 1999). 

Because concrete with rubber tire particles exhibit compressive strengths that are lower 
than normal mixtures, there have been a number of studies done to determine if the low 
strength of these mixtures can be improved. One area of investigation has been to 
examine the pretreatment of rubber particles prior to batch mixing. Techniques such as 
washing, etching and coating the rubber with different materials have yielded various 
results. Biel and Lee reported that the type of cement used in concrete containing rubber 
tire particles affected its strength. Their research showed that using magnesium 
oxychloride cement greatly increased the strength of a mixture containing rubber tire 



18 



particles (Biel and Lee 1996). Zhu and Zhang studied the use of crumb rubber in stucco 
coatings and mortar. A unique feature of their study was the use of latex to improve the 
strength of the stucco (Zhu and Zhang 2002). 

2.12.2 Flexural Strength 

Research on the flexural strength of concrete containing rubber tire particles followed the 
same pattern as the results on compressive strength. Mixtures with rubber tire particle 
replacements had flexural strengths that were lower than conventional concrete. Khatib 
and Bayomy did report that the initial rate of reduction was greater when compared to the 
results for compressive strength (Khatib and Bayomy 1999). 

2.12.3 Freeze-Thaw Durability 

Federoff et al. investigated the freeze-thaw durability of concrete that contained rubber tire 
particles in accordance with (ASTM C 666 1997). The results showed that as the amount 
of rubber particles increased the durability of the concrete mixture decreased. Only the 
mixtures with 10% and 15% replacement had durability factors higher than 60% when 
tested in accordance with (ASTM C 666 1997). Mixtures with higher amounts did not meet 
the 60% durability factor which is generally considered as a standard for acceptable 
performance of concrete subject to freeze-thaw action. The addition of an air entraining 
admixture did not significantly improve the durability of the mixtures (Federoff et al. 1996). 

2.12.4 Thermal Properties 

Because a number of studies have shown that the use of crumb rubber tends to reduce the 
compressive, tensile and flexural strength of concrete mixtures, studies have been 



19 



performed to investigate specific properties that might be enhanced by the addition of 
crumb rubber. Sukontasukkul examined the thermal properties of crumb rubber used in 
concrete precast wall panels. In the study a number of different mixtures containing 
different sizes of crumb rubber were used and compared to a control mixture. Mixtures 
containing 1 0%, 20% and 30% of crumb rubber with a water to cement ratio of 0.47 were 
made with each type of crumb rubber (Sukontasukkul 2009). 

The thermal conductivity of the mixtures was measured in accordance with (ASTM C 177 
1997). The results showed that the thermal conductivity, k of the mixtures containing 
crumb rubber were lower by about 20-50% than the control mixture. The study stated that 
the thermal conductivity of a material is inversely proportional to its density. As noted 
above, the density of crumb rubber is much less than aggregates used in concrete. 
Therefore, the addition of crumb rubber greatly improves the thermal properties of concrete 
mixture (Sukontasukkul 2009). 

2.12.5 Potential Health Hazards 

Although recycling of waste tire material meets beneficial goals such as conserving natural 
resources and preserving landfill space, the potential health hazards associated with its 
usage should be considered. (ASTM D 6270 2008) provides the standard practice for the 
usage of scrap tires in civil engineering applications and discusses acceptable limits for 
metals and organics of leachate from tires. Studies using waste tire material above and 
below the water table have been performed. In one study Humphrey conducted a field 
study to evaluate the water quality effects of tire shreds placed below the water table. 
Three sites were used in the study where tire shreds were buried in a trench below the 



20 



water table were studied. Monitoring wells up and down gradient of the trench as well as in 
the trench were installed to take water quality samples. The results indicated that the tire 
shreds had a negligible off-site effect on water quality (Humphrey 2001 ). 

One use of waste tires is in the production of artificial turf for athletic fields and surfaces for 
playgrounds. A recent study by the EPA evaluated air samples and metal samples in the 
field turf (EPA 2009). The report concluded that there were no known health concerns but 
there are gaps in the knowledge about the product. One difficulty in evaluating the health 
hazardous of turf fields is that the chemical composition of crumb rubber can vary among 
suppliers. The report recommended that future research be performed with a larger scope. 



21 



3. Problem Statement 

The interest in sustainable construction practices has led to a number of initiatives and 
incentives to promote strategies that use resources wisely. This has resulted in the re- 
evaluation of traditional construction practices and the use of recycled materials in some 
cases. Concrete masonry units are an important building material that is used on a variety 
of projects. Since advances in technical knowledge are important to providing a 
sustainable environment, this thesis will examine the use of concrete masonry units and 
determine if recycled aggregates can be used in the mixture design of the units. 

The reuse and disposal of solid waste has been a challenging problem in building a 
sustainable environment. Two materials that have received a lot of attention in recycling 
efforts have been waste glass and scrap rubber tire particles. Over the years a number of 
uses for these two items have been created and an industry has been developed to 
support these uses. Waste glass recycling typically involves the remolding of old glass into 
new containers such as bottles and jars. Crumb rubber is a by-product of recycling old 
tires and is currently being used successfully in the construction of asphalt pavement, 
playground surfaces and sports turf. This thesis will evaluate if the use of waste glass and 
scrap rubber tire particles can be expanded to serve as an aggregate replacement in the 
construction of concrete masonry units. Because there has been limited research in this 
area, it is the hope that the research will create new interest in the use of recycled 
materials in masonry block. 



22 



The focus of the research will be to examine the effect of the aggregate replacement in the 
mixture design used to produce concrete masonry blocks. Common properties of the 
concrete masonry units used by designers and required by engineering standards will be 
investigated. Most masonry units are made in an automated manufacturing process. 
Although it is difficult to replicate this process in the laboratory, the research will attempt to 
reproduce the conditions present in masonry manufacturing. 

A goal of the research is to investigate whether or not the use of waste glass and rubber 
tire particles will produce units that will meet minimum industry standards. It also 
investigates if there is any improvement or drawbacks in the performance of some 
properties of the concrete masonry units resulting from its usage. Finally, the 
constructability of units made from waste glass and rubber tire particles is examined. 



23 



4. Experimental Plan 

4.1 Laboratory Plan and Goals 

The objective of this research is to investigate the use of waste glass and rubber tire 
particles as an aggregate replacement in concrete masonry units. The research was 
defined by the following goals. 

1. Because the visual aesthetic appearance of masonry is an important criterion in 
determining its usage on construction projects, the use of recycled aggregates to 
replace coarse aggregates will not be considered in this research. Concrete 
pavement mixtures containing large pieces of recycled aggregate have been found 
to have exposed recycled aggregate after placement in the field. In order to 
correct this problem, the finishing crew had to embed or "poke" the aggregate 
down into the concrete. Large pieces of exposed aggregate are not acceptable in 
the manufacturing of concrete masonry units. Therefore, for this study, the usage 
of recycled aggregates was limited to replacement of fine aggregates only. 

2. In the construction industry, concrete masonry units are specified to meet the 
requirements of (ASTM C 90 2003). Therefore the research investigated meeting 
the requirements of this standard. If the units did not meet this standard, their 
potential as a construction material would be limited. 

3. Another focus is sustainable concrete masonry practices. The recycled materials 
of waste glass and rubber tire particles were used to determine if their use is a 
viable option for the construction of concrete masonry. 



24 



4. Replacement rates of the waste glass and rubber tire particles was examined and 
compared to a control mixture. 

4.2 Testing Concrete Masonry Mixtures in the Laboratory 

Typically cast concrete is produced as a plastic mixture, placed in a form, consolidated by 
various vibration techniques and cured until it has gained enough strength to be removed 
from the formwork. The production of concrete masonry units is an automated 
manufacturing process that is very different from most other methods of concrete 
production. The production consists of batch mixing materials that are then transferred to 
a mold assembly. Filling of the molds is accomplished by keeping extra material in the top 
of the mold assembly to ensure complete filling of the mold. The mixture is then 
consolidated by external vibration and direct pressure. The units are quickly removed from 
the mold and shipped to the curing operation. This cycle is repeated several times a 
minute. Typically a zero slump mixture is used that does not deform so that the concrete 
block can be quickly removed from the mold assembly and transferred to other areas of the 
production plant. The water content of a concrete block mixture is defined more by the 
amount of water that allows the units to progress though the production machinery than by 
strength requirements (Berg and Neal 1997). 

Currently, there is not a standard method of testing concrete masonry mixtures in the 
laboratory. Testing of trial mixtures of CMU units typically involves production of small 
batches on assembly line machinery. Often this is impractical and difficult to perform. 

Berg and Neal studied methods to evaluate concrete masonry unit mixtures in the 
laboratory (Berg and Neal 1997). The focus of their research was to replicate the unique 



25 



properties of production machinery using equipment available in most concrete 
laboratories. In their research, test samples consisted of 2-in by 2-in cubes instead of full- 
size concrete masonry units. The concrete mixtures were placed in the molds and then 
compacted. Concrete masonry units made by automated machinery do not meter the 
amount of material placed in the molds, but rather have a unique filling technique for 
transferring batched material to the mold assembly as described above. In order to 
duplicate this filling method, Berg and Neal determined the amount of material required to 
fill the mold based upon the anticipated required compaction and then weighed the 
material in a separate container. Half of the mixture was placed in the mold and 
consolidate followed by the remaining volume of material which was then compacted. 

The compaction of common concrete masonry machinery is probably the most difficult item 
to duplicate in the laboratory. Berg and Neal modified a Pine Instrument Company Model 
PMC-4 compactor, designed for compacting asphaltic samples for the Marshall method of 
mix design, to create a drop hammer for compacting the samples. The weight of the 
hammer, the number of drops and the height of the drop could be adjusted to achieve 
different levels of compaction for the concrete mixtures. The unit weight and texture of the 
specimens made in the laboratory were then correlated with full scale units produced on a 
supplier's production equipment to determine the required compaction effort. The 
specimens in Berg and Neal's research were removed from the molds after 2 hours. 

Because numerous mixtures were needed to determine a control mixture and the effect of 
various replacement rates of waste glass and rubber tire particles, smaller mixtures that 
produce 2-in by 2-in cubes were be used. Filling of the molds, compaction of the mixture 
and removal of the units from the molds resembled the work done by Berg and Neal. 



26 



4.3 Designing Concrete Masonry Unit Mixtures 

As mentioned above, the design of concrete mixtures for use in the production of concrete 
block is different than traditional concrete mixture design. ACI 21 1 .3R-02, Appendix 5, 
"Guide for Selecting Proportions for No-Slump Concrete", contains recommendations for 
the design of mixtures used in the manufacturing of concrete masonry units. Portland 
cement should conform to (ASTM C 150 2005). Type III and lll-A cements are often used 
to achieve early strength gain to facilitate the manufacturing process. Supplementary 
cementitious materials consisting of blast-furnace slag and fly ash can be used. The ACI 
guide recommends that the cement content of the mixture be calculated as a percent of the 
total mass of the aggregates (ACI 2009). 

Coarse aggregate is defined as material passing a 3/8 inch sieve and remaining on a No. 4 
sieve whereas fine aggregate consists of natural sand that passes a No. 4 sieve. Normal 
weight aggregates will be used in the research. The proportions of aggregates 
recommended to achieve an optimal fineness modulus can be determined from equation 
4.1 . ACI recommends a fineness modulus of 3.7 for normal weight aggregates. 



„ „ „ „ FMCA - FMcomb 

FA% = Equation 4.1 

(FMca-FMfa)x100 



FA% = Percentage of Fine Aggregate 

FMca - Fineness Modulus of coarse aggregates 

FM FA = Fineness Modulus of fine aggregates 



27 



FMcomb - Recommended Combined Fineness Modulus 

The amount of water used is determined during batch mixing so that the mixture will ball. 
ACI 21 1 states that the ball "will have sufficient cohesion to hold its shape when squeezed 
but will not exhibit any free moisture." (ACI 2009). Unlike other methods used to determine 
mixture proportions, the method of determining proportions for a concrete block involves 
trial and error. Test batches must be reviewed to evaluate the block's molded strength to 
determine if it can be transported through the limits of the manufacturing process. Also the 
compressive strength, surface texture and visual appearance of the trial batch should be 
reviewed during mixture testing. 

4.4 Materials 

The materials used in the concrete masonry mixtures consisted of Type l/ll portland 
cement that conforms to (ASTM C 150 2005). The coarse aggregates were prepackaged 
materials and the fine aggregates were sand from a local concrete supplier. All of the 
aggregates conformed to (ASTM C 33 2003). The recycled aggregates included crumb 
rubber and waste glass provided by a local supplier. Water used in all the mixtures was 
potable drinking water. Additional information on the materials used in the mixtures is 
included in Appendix A. 



4.5 Phase 1 - Determining Control Mixture Proportions and Calibrating Laboratory 
Equipment 



The use of a control mixture is important for establishing a standard by which to judge the 
effects of using recycled materials in concrete masonry units. The ideal control mixture 
would be an established mixture used by a local block manufacturer that has a large body 



28 



of test data performed on it. In talking with several concrete block producers, each supplier 
was reluctant to release their mixture designs out of concern of aiding a potential business 
competitor. Thus, this information was not available. The recommendations of ACI 21 1 
recognize that designing concrete masonry mixtures is a trial and error process (ACI 
2009). Therefore, the phase 1 work evaluated several control mixtures to determine if the 
mixtures meet the strength, visual appearance and other requirements of (ASTM C 90 
2003). Based upon the test results of the mixtures, one control mixture was established for 
use on the remainder of the research. 

Since producing concrete block in the laboratory is different than producing units thru an 
automated manufacturing process, the performance of the laboratory equipment and 
calibration of the compaction effort for the molds needed to be evaluated in this phase of 
the work. Fresh and hardened concrete properties for the control mixtures were recorded 
and analyzed. 

4.6 Phase 2 - Examination of Aggregate Replacement in CMU Mixtures 

Once a control mixture had been established and the laboratory equipment calibrated, 
mixtures with various amounts of recycled aggregate were made. Rubber tire particles and 
waste glass were used to replace the fine aggregate content of the established control 
mixture. Replacement rates of 10%, 20%, and 30% were investigated for the waste glass 
and scrap tire particles. Tests on fresh and hardened concrete properties were performed 
per Section 4.7. The effect of the replacement rate on various engineering properties was 
examined. 

4.7 Concrete Properties 



29 



The testing of cubes produced for the research followed the requirements found in (ASTM 
C 90 2003) and (ASTM C 140 2003). Concrete block produced in an automated 
manufacturing facility is often cured with steam at elevated temperatures for varying 
lengths of time. Because this is difficult to replicate in the laboratory, water curing of the 
units was performed. The following tests on samples of the mixtures were performed 
during Phase 1 and 2 unless noted otherwise. 

1 . The finish and appearance of the cubes were reviewed to determine if they 
conform to item 7 of (ASTM C 90 2003). The standard requires units to be sound 
and free of cracks or other defects. The color and texture of the block were 
reviewed to determine if it is possible to use the cubes in an exposed condition 
where the aesthetic appearance is an important criterion. 

2. The weight of each unit was determined and recorded. 

3. The water absorption of the units was examined to determine of they conform to 
Table 3 of (ASTM C 90 2003). 

4. The compressive strength of the units was reviewed and compared to the 
requirements of Table 3 of (ASTM C 90 2003). The testing machine used for the 
tests conformed to (ASTM E 4 1996). ASTM does not stipulate a time frame for 
testing units after they have been produced. Therefore, compression testing was 
performed after 7 and 28 days for the trail samples. Strength tests were performed 
to better understand how quickly the concrete block would gain strength and to 
facilitate the work flow of the research. 

4.8 Viability As A Construction Material 



30 



In order for waste glass and rubber tire particles to be used as an aggregate replacement 
in concrete masonry units, the units must meet current engineering standards. 
Nevertheless, this alone will not ensure their usage on normal construction projects. 
Additional items such as the ease of usage of the waste glass and rubber tire particles in 
constructing the concrete block need to be considered. During the course of the research 
difficulties with the use of the recycled materials were observed. This information was not 
be a definitive study of the applicability of the units, but rather done to give one some 
judgment as to whether or not their usage is reasonable. 



31 



Results 



5.1 Phase 1 - Determining Control Mixture Proportions and Calibrating Laboratory 
Equipment 



Phase 1 of the research involved assembling the materials to be used in the research and 
determining their physical properties. The laboratory equipment used was calibrated and 
tested for the research. Special devices such as a drop hammer to compact the trial 
mixtures were constructed for the work. Finally, a control mixture was developed with 
which to judge the results of other work against. 

5.2 Materials 

Materials used in the research were obtained from local suppliers and consisted of cement, 
pea gravel, sand, waste glass and rubber tire particles. The cement conformed to (ASTM 
C 150 2005) Type l-ll. Per ACI 211.3, in CMU production, generally material passing the 
3/8 in. sieve and remaining on the No. 4 sieve is considered as a coarse aggregate (ACI 
2009). Therefore, pea gravel was used as a coarse aggregate for the mixture designs. 
The fine aggregate used consisted of sand that conformed to (ASTM C 33 2003). 
Information on the chemical composition, soundness test on aggregates and other test 
data furnished by the suppliers of the materials are contained in Appendix A. 

Waste glass was used as a fine aggregate replacement and was supplied by a local bottle 
manufacturer. It consisted of recycled glass of all colors that was crushed by the supplier. 
The crushed glass was used by the bottling manufacturer to make new containers and was 



32 



used in this research to replace the sand in the mixture design. A photo of the waste glass 
is shown in Figure 5.1. 




Figure 5.1 Waste Glass 

The waste glass contained some trash items such as bottle caps, screws, batteries and 
other objectionable items. Because a 3/8 sieve was the largest sieve size that the coarse 
aggregate used in the research was retained on, the glass was run through a 3/8" sieve to 
remove the larger trash items. This removed a majority of the objectionable items, but not 
all of them. Passing the material through a finer sieve may have removed more trash 
particles, but it would have begun to remove large pieces of waste glass material. A 
picture of the trash items found in the waste glass is shown in Figure 5.2. 



33 




Figure 5.2 Trash in Waste Glass 

Crumb Rubber was also used as an aggregate replacement. The rubber was supplied by 
a sports turf supplier. A photo of the crumb rubber is shown in Figure 5.3. 




imi'ii 



Figure 5.3 Crumb Rubber 



34 



5.3 Gradation Test 

Gradation tests were performed on the fine and coarse aggregates, waste glass and 
rubber tire particles used in accordance with (ASTM C 136 2005). During the test, care 
was taken to dry the materials to prevent clumping and the samples were divided into parts 
as recommended by the ASTM standard to prevent pan overloading. The sand for the 
mixtures conformed to the gradation requirements of (ASTM C 33 2003). As noted above, 
trash items in the waste glass were removed by passing the material through a 3/8" sieve. 
This was done prior to performing the gradation test. The waste glass compared favorably 
to the gradation of the sand. The results of the gradation test for the fine aggregate are 
summarized in Table 5.1 and Figure 5.4. 

Table 5.1 Gradation test of fine aggregates 



Sieve Size 


Percent Passing 


ASTM 
Requirements 


Sand 


Waste Glass 


Crumb 
Rubber 


3/8 


100 


100 


100 


100 


No. 4 


95-100 


100 


99 


100 


No. 8 


80-100 


98 


96 


99 


No. 16 


50-85 


78 


78 


76 


No. 30 


25-60 


48 


56 


16 


No. 50 


5-30 


18 


28 





No. 100 


0-10 


4 


9 





No. 200 


0-3 


0.9 


2 





Fineness Modulus 


2.3-3.1 


2.55 


2.36 


3.09 



35 



Gradation Comparison of Fine Aggregates 



D3 

'o 



>1 

_c 
□o 

c 
'(/> 
tr> 
to 

D. 

-i— 

C 

o 
o 
i_ 
o 

Q. 



120 



100 



30 



60 



40 



20 





































< 


/'] 
















7 1 










> 


If • 


' / 










^'\ 


r 













0.1 



10 



Sand 



Grain Diameter (mm) 

-Waste Glass — ■ — Crumb Rubber 



Figure 5.4 Gradation of Fine Aggregates 

Pea gravel was used for the coarse aggregate in the mixture. The gradation of the 
material conformed to a number size 8 in accordance with (ASTM C 33 2003). The results 
of the gradation test are summarized in Table 5.2 and Figure 5.5 

Table 5.2 Gradation test of coarse aggregates 



Sieve Size 


Percent Passing 


ASTM Size No. 8 


Pea Gravel 


1/2 


100 


100 


3/8 


85-100 


97 


No. 4 


10-30 


30 


No. 8 


0-10 


3 


No. 16 


0-5 


1 


Fineness 
Modulus 




5.69 



36 



Pea Gravel Gradation Test 



'o 



jQ 

OD 

C 
'if> 
CO 

re 
Q. 

c 
o 
o 

1_ 

o 

0. 




0.1 1 10 

Grain Diameter (mm) 



100 



Figure 5.5 Gradation of Coarse Aggregates 

5.4 Dry Rodded Unit Weight 

The dry rodded unit weight of the materials was determined in accordance with (ASTM C 
29 1997). Samples were dried to a constant mass weight and then weighed in a calibrated 
measure. Results are shown in Table 5.3. 



Table 5.3 Unit weight of aggregates 



Unit Weight 



Pea Gravel 
pcf 



Sand 
pcf 



Waste Glass 
pcf 



Crumb Rubber 
pcf 



Dry Rodded 



101.1 



103.6 



84.8 



29.4 



5.5 Control Mixture Proportions 

Once the properties of the individual mixture materials were determined, a control mixture 
was developed. Because a control mixture could not be provided by a local manufacturer, 



37 



it was determined in accordance with ACI 21 1 .3R. Most concrete mixtures are determined 
by the absolute volume method, but ACI 21 1 .3R recommends a method that relies on trial 
and error. First the percentage of fine and coarse aggregates was determined from the 
recommendations of ACI 2113R per Equation 5.1 



_, . . . FMCA - FMcomb 

FA% = Equation 5.1 

(FMca-FMfa)x100 



FA% = Percentage of Fine Aggregate 
FMca = 5.69 (See Table 5.2) 

Fineness Modulus of coarse aggregates 
FM FA = 2.55 (See Table 5.1) 

Fineness Modulus of fine aggregates 
FMcomb = 3.70 

Recommended Combined Fineness Modulus 

The percentage of fine aggregate, FA% was determined to be 63.2% and the percentage 
of coarse aggregate, CA% was 36.8%. 

Next the volume of the trial mixture was selected. The weight of the fine and coarse 
aggregates was determined as the product of the mixture volume, the dry rodded unit 
weight of the aggregate and the percentage of the aggregate determined from equation 
4.1 . The cement factor was assumed as a percentage of the aggregates. Because a test 
history and information on a trial mixture were unavailable, four mixtures with cement 
factors of 10%, 15%, 20% and 25% were investigated and the properties of the mixtures 



38 



reviewed. The cement content was the product of the cement factor and the combined 
weight of the fine and coarse aggregates. In the work that follows, the terms cement factor 
and percent cement should be considered interchangeable unless noted otherwise. 
Sample calculations of a mixture from ACI 21 1 .3R are included below: 

Material Properties 

FA% = 61% 

CA% = 39% 

FA density (dry-rodded) = 95 pcf 

CA density (dry-rodded) = 76 pcf 

Mixture Proportions 

Mixture Volume = 78 cubic ft 

Mass of FA = 78 cubic ft (0.39) (76 pcf) = 2312 lb 

Mass of CA = 78 cubic ft (0.61 ) (95 pcf) = 4520 lb 

Total Mass of Aggregates = 6832 lb 

Cement factor: assume 1 0% by mas of aggregate 

Cement content = 6832 (0.1) = 683 lb 

In accordance with ACI 21 1 .3R Appendix 5, the water content of CMU mixtures should be 
adjusted until the mixture will "ball" in the hand. This is defined as having enough cohesion 
to hold its shape when squeezed while not exhibiting any free moisture (ACI 2009). 
Therefore, trial mixtures with the four cement factors mentioned above were examined to 
determine the amount of water required for the mixture to ball. The procedure for this 
consisted of mixing the dry components in a counter top mixer for 2 minutes followed by 



39 



adding water and additional mixing for 4 minutes. The mixture was then hand squeezed to 
see if balling had occurred. Next water was added in increments of a w/c ratio of 0.1 and 
the mixture remixed for a total of 3 minutes. After each addition of water, a squeeze test 
was performed and the condition of the mixture noted. Care was taken to start the mixture 
test with a w/c ratio that would not ball and then add water until the mixture was beyond the 
point of balling. The results of the test are summarized in Figures 5.6 and 5.7. Results are 
approximate and the test is a subjective test, but it defined a point at which to evaluate the 
various mixtures. 



0,8 




10 15 20 

Percent Cement (% ) 



25 



30 



Figure 5.6 Water to Cement Ratio at Which Mixture Will Ball 



40 




Figure 5.7 Squeeze Test 

After the water content for the mixture design was determined, trial mixture batches with 
the mixture proportions shown in Table 5.4 were used to determine the control mixture. 

Table 5.4 Mixture proportions of trial control mixtures 



Properties 


10% Cement 


15% Cement 


20% Cement 


25% Cement 


Sand (lb) 


2.618 


2.618 


2.618 


2.618 


Pea Gravel (lb) 


1.489 


1.489 


1.489 


1.489 


Cement (lb) 


0.411 


0.616 


0.821 


1.027 


Water (lb) 


0.288 


0.370 


0.411 


0.411 


Water to Cement Ratio 


0.7 


0.6 


0.5 


0.4 


Mixture Volume ft J 


0.04 


0.04 


0.04 


0.04 



Mixing of trial control mixtures was done with a small counter type mixer until it appeared 
that components were adequately mixed by visual inspection. The dry components were 
mixed for 2 minutes and the mixture was agitated for 4 minutes after the water was added. 
Mixtures were placed in cube molds conforming to (ASTM C 109 2002) and the sides of 
the molds were coated with a thin layer of form release agent to break the bond between 



41 



the mold and concrete mixture. The molds were then placed in a moisture and 
temperature controlled room for one day before being removed from the molds. The cubes 
were then weighed and cured by placing them in a saturated lime water storage tank. 

The moisture content of the aggregates of the control mixtures was checked in accordance 
with (ASTM C 566 1997) and is shown in Table 5.5. 

Table 5.5 Moisture content of aggregates 



Aggregate 


Moisture Content 


Sand 


0.16% 


Pea Gravel 


0.17% 


Crumb Rubber 


0.45% 


Waste Glass 


0.05% 



5.6 Compaction 

In CMU production, a concrete mixture is placed in molds and consolidated by external 
pressure and vibration. In their paper "A Procedure for Testing Concrete Masonry Unit 
(CMU) Mixes by Eric Berg and John Neal, the authors state that "there is no accepted 
method of duplicating the manufacturing process of CMU in the laboratory. Specifically the 
vibration compaction method of a production CMU machine is the most difficult part of the 
process to recreate in the laboratory (Berg and Neal 1997)." 

Several compaction methods were investigated to achieve the desired compaction and unit 
weight. The first method of compaction used was tamping of the mixture in the molds in 
accordance with (ASTM C 109 2002). A layer of material 1 inch deep or approximately 
one half of the mold depth was placed in all of the cells of the mold. The material was 
tamped a total of 32 times consisting of 8 strokes in four rounds with each round at right 



42 



angles to the previous round. When one cell of the mold was compacted, the next cell was 
filled and compacted in a similar fashion until all of the cells were completed. After 
completion of compaction of the first layer, additional material was placed and the top layer 
compacted. This method by itself was found to be insufficient to compact the cubes, so a 
hammer drop was added. The hammer drop consisted of a various weights dropped at 
different measured heights. This allowed the compaction effort to be quantified and 
duplicated. A collar or dam was added to the molds to allow for overfilling of the mold 
similar to what happens in the manufacturing of CMU units. The drop hammer and collar 
are shown in Figure 5.8 and 5.9. 




Figure 5.8 Drop Hammer Compaction Equipment 



43 




Figure 5.9 Collar for Mold 

Originally the tamping was done in two layers and the hammer drop was applied to the top 
of a filled mold similar to a CMU machine overfilling its mold and applying pressure for 
consolidation. Even under this second method of compaction, voids and areas with low 
consolidation areas were noticed in the cubes produced, particularly in the middle of the 
cube. Therefore the method of tamping per (ASTM C 109 2002) was replaced with rodding 
of the mixture. A % inch diameter rod was used that allowed one layer to be pushed into 
another layer providing interlayer mixing and consolidation. The molds were filled to a 
depth of about 1 inch and then consolidated by rodding and using the hammer drop. The 
cube was then overfilled and again consolidated by rodding and using the hammer drop. 
Applying the hammer drop to two layers of the mold allowed the area in the middle of the 
cube to be well compacted. The rodding pattern used consisted of 18 strokes or 9 strokes 
in 2 rounds with each round at right angles to the other. The weight and drop of the 
hammer drop was adjusted to achieve the desired compaction. 



44 



As the compaction methods were reviewed and the compaction effort calibrated, a study of 
the unit weight of the 2-in. x 2-in. cubes versus their 7 day compressive strength was 
performed. A mixture with a cement factor of 10% was used and the unit weight of the 
cubes were recorded when they were removed from the mold prior to water curing. At this 
point the cubes still had a significant amount of moisture which would result in a unit weight 
slightly greater than their final condition. Mixture proportions, mixing methods, sample 
production and curing for the samples were as noted above. The results of the study are 
shown in Figure 5.10. At unit weights lower than about 125 pcf, the strength of the 
samples appear to be greatly affected by the amount of compaction effort used. 

In their research, "A Procedure for Testing Concrete Masonry Unit (CMU) Mixes", Berg and 
Neal produced units that matched to a local CMU producer's unit weight of 133.5 pcf (Berg 
and Neal 1997). James Amrhein in "Reinforced Masonry Engineering Handbook" lists the 
unit weight of normal weight masonry as 135 pcf (Amrhein 1983). Therefore, based upon 
this literature review and the limited study performed in the laboratory, it seems reasonable 
to calibrate the compaction effort to produce test samples with a unit weight of 
approximately 135 pcf. This unit weight target was used to calibrate the compaction effort 
for the research. 



45 



7 Day Strength vs. Unit Weight 



700 



CO 


600 


c 
o 

71 


500 
400 


o 
> 


300 


CO 
CO 

c 

1_ 


200 


E 
o 


100 



o 



; 
















; 










635 


645 


- 


\ 














- 


I 




326.7 










- 


1 
















1 


116.7 












- 


; 














- 



4.0 



3.0 



2.0 



1.0 



0.0 



0. 



□3 

c 
o 

1_ 

4— 

00 
o 
> 
■» 

CO 

o 

Cl 

E 
o 
O 



100 105 110 115 120 125 130 135 140 

1 Day Unit Weight (lb/ft 3 ) 

Figure 5.10 7 Day Compressive Strength vs. Unit Weight 

5.7 Phase 1 Results 

After the mixture proportions were calculated and the compaction effort determined, four 
trial mixtures were produced and their properties evaluated. The mixing of the samples, 
compaction and curing were as noted above in Section 5.5. The same compaction effort 
was used for all of the trial mixtures. The reported values are the average of results from 
three cube samples unless noted otherwise. The figures produced simply connect data 
points and do not attempt any curve fitting of the data. The results of each individual 
specimen are contained in Appendix B. Plots of the scattered data and the development of 
trendlines are also contained in Appendix B. 

During the research, the samples remained in their molds for 1 day before they were 
removed. After compaction, the cubes had enough green strength to be removed from 



46 



their molds and retain their shape, but care had to be exercised in moving the samples 
about the lab. Figure 5.11 shows cubes removed immediately from their mold after 
compaction. 




Figure 5.1 1 Cubes Removed from Mold Immediately After Compaction 
In accordance with (ASTM C 90 2003), the finish and appearance of the masonry units 
shall be sound and free of cracks or other defects. The cubes produced did not have any 
cracks or other surface defects. The visual appearance resembled typical masonry units. 
A typical cube is shown in Figure 5.12. 



47 




Figure 5.12 Cube Produced - Top View 

Table 2 of (ASTM C 90 2003) sets the amount of absorption for normal weight CMU at a 
maximum value of 13 pcf. Absorption was calculated in accordance with the following 
formula given in (ASTM C 140 2003). 

Absorption (pcf) = (W s -W d /W s -Wi)x 62.4 Equation 5.1 

W s = saturated weight of unit 

W d = dry weight of unit 

W, = weight of the unit immersed in water 

All of the trial mixtures tested met the criteria set forth in Table 2. Results of the absorption 
test are shown in Figure 5.13. In general as the cement content of the mixture increased, 
a more dense mixture was produced and the absorption of the unit decreased. The 



48 



absorption was determined after curing for 7 days. Because it was thought that the 
mixtures with a cement factor of 15% and 20 % might be used as a control mixture 
additional testing at 28 days was performed. There was very little difference between the 7 
and 28 day absorption values recorded. 



Absorption vs. Percent Cement 



£ 
£ 



c 
o 



o 

U) 

< 




15 20 

Percent Cement (%) 
1 7 -Day Absorption □ 28 -Day Absorption 






c 
o 



o 

< 



Figure 5.13 7 Day and 28 Day Absorption 

The weight of the cubes for the four trial mixtures was recorded after curing for 7 days and 
then being placed in a moisture and temperature controlled room for 3 days. This allowed 
the samples to reach a moisture content at which they might be used. The results are 
shown in Figure 5.14. In general, the unit weight of the mixtures increased as the cement 
factor or percent of cement used increased. This is to be expected given the high specific 



49 



gravity of cement when compared to the other mixture components. The 28 day unit 
weight was determined for the mixtures with a 15% and 20 % cement factor and their 
weight was virtually the same as that recorded after 7 days. 



Unit Weight vs. Percent Cement 






■p 






140 



135 



130 



125 



120 



- 








138 J 


fc 






130.1 


133.7J 




: 




125 








1 












z 



2222 



2172 ^ 






2122 



2072 .H> 

I 
2022 - 

c 

1972 



1922 



10 



15 



20 



25 



30 



Percent Cement (%) 

Figure 5.14 Unit Weight of Trial Mixtures 

The compressive strength of the trial mixtures was examined. (ASTM C 90 2003) requires 
a minimum strength of 1900 psi for concrete block, but specified no time frame at which the 
strength is required. Typically in masonry production, long curing times are not common. 
Two studies were performed to evaluate the strength of the masonry. The first developed 
a family of curves based upon different water to cement ratios for a certain cement factor. 
The 7 day strength results are shown in Figure 5.15. In general it showed that lower water 
to cement ratios resulted in greater strengths. 



50 



Strength vs. Waterto Cement Ratio 



3500 



3000 



CO 




a. 


2500 






c 

o 


2000 


(J 
> 


1500 


(/I 

CO 

•J 




Q. 


1000 


E 
o 
O 


500 



: 


3166 












- 


: 








2448 






- 


: 














- 


: 






17S3J 






1466 




: 














- 


: 










653 




666 






: 














- 



20.0 ^ 
0. 



15.0 



10.0 



5.0 



0.0 



0.4 0.45 0.5 0.55 0.6 0.65 0.7 0.75 0.8 
Waterto Cement Ratio 



CD 

c 
o 
i_ 

w 
o 
> 

"to 

CO 

c 



o 
O 



•10% Cement 



•15% Cement 



•20% Cement 



Figure 5.15 Compressive Strength vs. Water to Cement Ratio - Trial Mixtures 

A second set of curves was developed based upon the water to cement ratio only at which 
the mixtures would ball for a certain cement factor. This is shown in Figure 5.16. The 7 
day strengths of the mixtures for a cement factor of 1 0%, 1 5% and 20% were reviewed. 



51 



7 Day Strength 



4000 
~ 3500 

"pr 3000 

2500 
2000 



3783 



c 
o 

I— 

55 





■^ 1500 

CO 

CO 



a. 

E 
o 
O 



1000 



500 



; 








► 


: 








-_ 










; 


; 




2113 § 




- 


; 








" 


; 


771 






; 


; 








1 


i 








\ 



25.0 



20.0 



re 
Q. 



15.0 £ 
CO 

CD 

10.0 I 

CO 



5.0 



0.0 



Q. 

E 
o 
O 



10 



15 



20 



25 



Percent Cement (%) 

Figure 5.16 Compressive Strength vs. Percent Cement - Trial Mixtures 

Based upon the data from the phase 1 work, the trial mixture with a cement factor of 15% 
was selected as a control mixture for the remaining work. A summary of the properties of 
the control mixture is shown in Tables 5.6. 

Table 5.6 Mixture proportions of control mixture 



Properties 


Control Mixture 


Sand (lb) 


2.618 


Pea Gravel (lb) 


1.489 


Cement (lb) 


0.616 


Cement Factor 


15% 


Water (lb) 


0.370 


Water to Cement Ratio 


0.6 


Mixture Volume cf 


0.04 



5.8 Phase 2 - Effect of Aggregate Replacement with Recycled Materials 

The control mixture from the Phase 1 work was used a standard to evaluate the effect of 
replacing the fine aggregate with waste glass and rubber tire particles in the mixture 



52 



design. Replacement rates of 10%, 20% and 30% were examined. In these mixtures, a 
certain percentage of fine aggregate by weight was removed from the control mixture and 
replaced with an equal volume of recycled materials. A. mixture designated 10% Waste 
Glass or 1 0% Crumb Rubber indicates that 1 0% of the weight of the fine aggregate or sand 
was removed from the mixture and replaced by an equal volume of waste glass or rubber 
tire particles. The mixture proportions for mixtures made with waste glass and rubber tire 
particles are shown in Tables 5.7 and 5.8. 



Table 5.7 



Proportions of mixtures containing waste glass 



Properties 


10% Waste 
Glass 


20% Waste 
Glass 


30% Waste 
Glass 


Sand (lb) 


2.3562 


2.0944 


1.8326 


Waste Glass (lb) 


0.2143 


0.4286 


0.6429 


Pea Gravel (lb) 


1 .4890 


1 .4890 


1 .4890 


Cement (lb) 


0.6161 


0.6161 


0.6161 


Water (lb) 


0.3696 


0.3696 


0.3696 


Water to Cement 
Ratio 


0.6 


0.6 


0.6 


Mixture Volume cf 


0.04 


0.04 


0.04 



Table 5.8 Proportions of mixtures containing crumb rubber 



Properties 


10% Crumb 
Rubber 


20% Crumb 
Rubber 


30% Crumb 
Rubber 


Sand (lb) 


2.3562 


2.0944 


1.8326 


Crumb Rubber (lb) 


0.0743 


0.1486 


0.2229 


Pea Gravel (lb) 


1 .4890 


1 .4890 


1 .4890 


Cement (lb) 


0.6161 


0.6161 


0.6161 


Water (lb) 


0.3696 


0.3696 


0.3696 


Water to Cement 
Ratio 


0.6 


0.6 


0.6 


Mixture Volume cf 


0.04 


0.04 


0.04 



Mixing was done in a similar fashion to that of the Phase 1 work where the dry components 
were mixed for 2 minutes. Then water was added to the mixture and all of the components 



53 



were mixed again for 4 minutes. After completion of mixing, the material was placed in 
cube molds conforming to (ASTM C 109 2002) and compacted. In reviewing the data on 
the control mixture the phase 1 work, it was determined that the unit weight of the 
specimens was slightly lower than the established goal of 135 pcf, so additional 
compaction of the mixtures was provided in the phase 2 work. The compaction 
methodology was the same as the work done in phase 1 and consisted of rodding and the 
use of a drop hammer. The distance the weight fell and the number of drops used for the 
drop hammer was increased slightly in phase 2 to produce a denser specimen. The same 
compaction effort was used for all mixtures evaluated. 

A thin layer of form release agent was used to break the bond between the mold and 
concrete mixture. After filling of the molds, the specimens were placed in a moisture and 
temperature controlled room for one day. The cubes were then removed from their mold, 
weighed and cured by placing them in a saturated lime water storage tank. The reported 
values are the average of results from three cube samples unless noted otherwise. The 
figures produced simply connect data points and do not attempt any curve fitting of the 
data. The results of each individual specimen are contained in Appendix B. Plots of the 
scattered data and the development of trendlines are also contained in Appendix B. 

During mixing of the specimens, the mixtures with recycled materials didn't appear to be 
noticeably more difficult to compact or mix than the control mixture. Gloves were required 
when working with the waste glass during mixing and filling of the molds to prevent being 
cut by the glass. Because concrete block is produced in an automated process, concerns 
about cuts to humans during the production of the block may not be a significant issue. 



54 



The surface texture of the block in its finished condition is discussed at the end of this 
section. 

When the cubes were removed from their molds after 1 day, their weight was recorded 
before they were immersed in water for curing. At this point the cubes still had a significant 
amount of moisture that would be greater than that of the final condition and had not cured. 
The recorded weights were the average of 6 cube samples and were useful in determining 
the effect on the unit weight of the recycled materials and are shown in Figure 5.17. 



1 Day Unit Weight 



£ 
3 









145.0 



140.0 



135.0 



130.0 



125.0 



138.49 



137.83 



136.64 







2302 



2252 



10 20 30 

Percent Fine Aggregate Replacement (%) 
— A- Waste Glass — ■ — Rubber Tire Particles 

Figure 5.17 1 Day Unit Weight vs. Percent Fine Aggregate Replacement 



55 



A separate study of the weight of the cubes was performed after they had been cured for 7 
days and then placed in a moisture and temperature controlled room for 3 days. This 
allowed the specimens to reach a moisture content similar to that which they might be 
used. The results are shown in Figure 5.18. 



7 Day Unit Weight 



3 



'o 






145.0 



140.0 



135.0 



130.0 



125.0 



- 










- 


137.7 


" - -A 


136.5 
t ' 


136.9 


: 


- 








■v 


N 
N 

131.3 a 


- 


131.0 




129.6 




128.5 : 



2302 



2252 



2202 D) 



2152 W 



2102 



2052 



2002 



10 20 

Percent Fine Aggregate Replacement (%) 



30 



— A- Waste Glass 



■Rubber Tire Particles 



Figure 5.18 7 Day Unit Weight vs. Percent Fine Aggregate Replacement 

The results from the 1 and 7 day unit weights show that as the amount of fine aggregate 
replacement increased the unit weight decreased. The mixtures made with rubber tire 
particles decreased at a greater rate than mixtures made with waste glass. This is to be 
expected given that the dry rodded unit weight of the crumb rubber was only 28% of that 
the sand and unit weight of the waste glass was 82% of the sand used in the mixtures. 



56 



The average of the 1 and 7 day unit weight studies showed that the unit weight of mixtures 
with waste glass replacement rates of 10%, 20% and 30% decreased 0.8%, 0.9% and 
3.4% respectively when compared to the control mixture. The mixtures containing rubber 
tire particles had a unit weight that decreased 3.8%, 5.1% and 7.0% for the same 
replacement rates. 

The absorption of the mixes was tested in accordance with (ASTM C 140 2003) and the 
results are shown in Figure 5.19. The absorption was tested on samples cured for a total 
of 7 days. The mixtures made with waste glass did not vary significantly from that of the 
control mixture whereas the mixtures made from rubber tire particles showed a slight 
increase as the replacement rate of rubber tire particles increased. The higher absorption 
rates for mixtures made with large replacement rates of rubber tire particles may indicate 
that the durability of these mixtures may be slightly less than that of the control mixture. 

Absorption vs. Percent Fine Aggregate Replacement 

7.92 




120 


— - 




F 






110 










C 




O 


100 


^ 




Q. 




L_ 




o 


9(1 


CO 




< 



SO 



10 20 30 

Percent Fine Aggregate Replacement 

■ Control Mixture DWaste Glass Rubber Tire Particles 
Figure 5.19 Absorption vs. Percent Fine Aggregate Replacement 



57 



The compressive strength of the mixtures with recycled materials was examined and the 
results of the 7 day strengths are shown in Figure 5.20. (ASTM C 90 2003) has no time 
requirement for determining the strength of concrete masonry units and only stipulates that 
they meet a minimum strength requirement of 1900 psi. Therefore, the strength of the 
units both at 7 and 28 days was reviewed. In general the compressive strength of the 
mixture decreased as the percent of aggregate replacement increased. The decrease in 
the rubber tire particle was greater than that of the waste glass. 

7 Day Strength 

17.5 





2600 




2400 


a. 


2200 
2000 


CO 


1800 


o 
> 

» 

■J 

a. 

E 
o 
O 


1600 
1400 


1200 




1000 




800 



: 2356 










- 


^" ~"~ 


k 


,2293 








\. 




*■>!» 

* 




1932 


1977 ; 


^ 








If" ~~ 


— —A 


| 










- 


\ 


1507 1 








■ 


I 






1372 






\ 










Sw 


\ 










824S. 



15.5 



11.5 



9.5 



7.5 



5.5 



5 10 15 20 25 30 

Percent of Fine Aggregate Replacement (%) 

it Waste Glass M Rubber Tire Particles 
Figure 5.20 7 Day Strength vs. Percent Fine Aggregate Replacement 



re 
0. 



CD 
C 
O 
i_ 

4— 

00 
o 
> 

■» 

<f> 
a 
i_ 

E 
o 
o 



58 



As recycled aggregate is added to a mixture, the strength of the mixture becomes less than 
that of the control mixture. Therefore one could say the use of recycled aggregate causes 
a strength reduction in the mixture when compared to the control mixture. 
A plot of the strength reduction for each mixture compared to the control mixture is shown 
in Figure 5.21 . This information is helpful in understanding the effect of the recycled 
aggregates and in comparing the results to other studies. 

7 Day Strength Decrease From Control Mixture 



Percent of Fine Aggregate Replacement (%) 



10 



20 



30 




j 0.0 

^ -10.0 

~s> 

I -200 

CO -30.0 

I -40.0 

S - 500 

8 -60.0 
Q 

-70.0 



□ Waste Glass Rubber Tire Particles 

Figure 5.21 7 Day Strength Decrease vs. Percent Fine Aggregate Replacement 

The 28 Day compressive strength of the mixtures with recycled materials was examined 
and the results are shown in Figure 5.22. The trend of the results showed a similar pattern 
to that of the 7 day strength results. 



59 



28 Day Strength 



co 

Q. 



c 
'J 

L_ 
■i— 

to 
o 
> 

CO 
CO 

-J 

Q. 

E 
o 
O 





. 














- 










- 


3nnn ■ 


- 2989 










-_ 


2500 
2000 


N^ 


s. 








1 


- 




2243 


■— . _,_ | 


2095 


2026 


- 


2071 










1500 


- 










- 












_ 




- 






1645 




.1044 : 


1000 


- 




, , , 






, rii 



re 
Q. 



□a 

c 
o 
i_ 

4— 

to 

o 
> 
w 

CO 

o 

l_ 
CL 

E 
o 
o 



22.9 

20.9 

18.9 

16.9 

14.9 

12.9 

10.9 

8.9 

6.9 
5 10 15 20 25 30 

Percent of Fine Aggregate Replacement (%) 
k Waste Glass M Rubber Tire Particles 

Figure 5.22 28 Day Strength vs. Percent Fine Aggregate Replacement 

A plot of the strength reduction when compared to the control mixture for each percentage 
of recycled aggregate is shown in Figure 5.23. 



60 



28 Day Strength Decrease From Control Mixture 
Percent of Fine Aggregate Replacement (%) 



10 



20 



30 




c 
o 

55 

£ 

O 
tfi 
TO 

i_ 
(J 

1: 

Q 



□ Waste Glass Rubber Tire Particles 
Figure 5.23 28 Day Strength Decrease vs. Percent Fine Aggregate Replacement 

The results showed that for replacement rates of 1 0%, 20% and 30% of waste glass, a 
strength decrease of 25%, 29.9% and 32.2% respectively occurred when tested after 28 
days of curing. Comparing the results of this study to work done in other research may be 
helpful in understanding the effects of the recycled aggregates, but it can be difficult for a 
number of reasons. The materials used, mixture proportions, replacement rates and focus 
of the research can vary greatly among studies making comparison difficult. 

In Section 2.4, it was noted that Meyer et al. did a study on the use of waste glass in 
concrete block. In this study, the amount of replacement of waste glass was limited to 10% 
of the fine aggregate because of concerns with alkali-silica reaction. Meyer et al. found 
that masonry lost about 8.9% of its strength for a replacement rate of 10% when tested 
after 28 days. This is higher than the results of this study, but it should be noted that the 



61 



water to cement ratio used in the mixture of the study done by Meyer et al. was very 
different using a ratio of 0.17 instead of the 0.6 ratio used in this study (Meyer etal. 2001). 

There have been a number of studies using waste glass in concrete. In comparing the 
results to work done in other studies the trend of the data matches that found in other 
research. As the amount of waste glass increased, the strength decreased. As noted in 
Section 2.7.1, Topcu and Canbaz studied coarse aggregate replacement rates of 15%, 
30%, 45% and 60% and found a strength decrease of 8%, 15% 31% and 49% (Topcu and 
Canbaz 2004). It should be noted that the replacement rates represent total aggregate 
replacement not just fine aggregate replacement. Park et al. in their study examined fine 
aggregate replacement rates of 30%, 50% and 70%, finding a strength decrease of 0.6%, 
9.8 and 13.6% respectively (Park et al. 2004). The results of this study show similar 
strength reductions to the work of Topcu and Canbaz, but were greater than the research 
of Park et al. Still comparing concrete block production to much higher strength concrete 
studies should be done with caution. 

The results showed that for replacement rates of 1 0%, 20% and 30% of crumb rubber 
resulted in a greater strength decrease of 30.7%, 40.3% and 65.1% respectively when 
tested after 28 days of curing. As noted in Section 2.9, there have been very limited 
studies in using rubber tire particles in concrete block. Cairns et al. did a study where 
coarse aggregate was replaced with rubber tire particles. The study showed that for 
replacement rates of 10%, 25% and 50%, strength reductions of 22%, 23% and 41% 
occurred. It should be noted that the proportions of fine and coarse aggregate in the study 
done by Cairns was very much different than that used in this study (Cairns et al. 2004). 



62 



Studies using crumb rubber in concrete have demonstrated that as the amount of crumb 
rubber increased the strength of the mixture decreased dramatically. The results of this 
study showed a similar trend. As noted in Section 2.12.1 , a study by Ghaly and Cahill with 
replacement rates of 5%, 10% and 15% of the total volume of the mixture saw strength 
reductions of 21 .7%, 48% and 59.7% respectively for a mixture with a water to cement 
ratio of 0.54 when tested after 28 days of curing (Ghaly and Cahill 2005). 

In summary, comparing the results to other studies shows similar strength reduction 
trends. The value of the strength reduction are similar, but it appears that the reduction 
may be slightly higher for mixtures of concrete block, possibly due to the low paste content 
of zero slump mixture design. 

The 7 and 28 Day compressive strength of the mixtures with recycled materials was plotted 
and the results are shown in Figure 5.24 and 5.25. 



63 



Waste Glass Strength Curves 



CO 
Q. 



c 
o 

55 
o 
> 

CO 
'.: 
i_ 
Q. 

E 
o 

O 





: 










- 


2500 












- 












- 


2000 
1500 
1000 

500 
















- 












- 












- 












- 



5 10 15 20 25 

Percent of Fine Aggregate Replacement (%) 
-m-7 Day Strength — *— 28 Day Strength 



20.0 „ 

CD 

Q. 



15.0 



10.0 .2 



5.0 



0.0 



30 



CD 

c 
o 

55 
o 
> 

CO 
CO 

c 

Q. 

E 
o 
O 



Figure 5.24 7 and 28 Day Strength Curves for Waste Glass Mixtures 



64 



RubberTire Particle Strength Curves 



3500 





3000 


^_^ 




CO 


2500 


Q. 




- — - 




x: 










2000 


o 












y> 




o 


1500 


> 




CO 




CO 




c 

1_ 


1000 


Q. 




E 




o 




O 


500 



: 










- 


^S,. 










- 












- 


N 


^ 

\ 








- 


; 






-11^^ 


"■^^"""Si 


; 










II 


; 










- 



20.0 






15.0 £ 

CD 

c 
o 



CO 
o 
> 

CO 

c 

CL 

E 
o 
O 



10.0 



5.0 



0.0 



5 10 15 20 25 

Percent of Fine Aggregate Replacement (%) 

-■ - 7 Day Strength — *— 28 Day Strength 



30 



Figure 5.25 7 and 28 Day Strength Curves for Rubber Tire Particle Mixtures 

Although it is difficult to see a definitive trend in the data of the two curves, the results may 
suggest that there is less of a difference in the strength of the 7 and 28 day samples at 
higher replacement rates. 

(ASTM C 90 2003) requires that the finish and appearance of the concrete masonry units 
be sound and free of cracks or other defects that might interfere with the proper placement 
of the units or impair their strength. Minor cracks and chips due to customary handling are 
not grounds for rejection. Five percent of shipments containing chips not larger than 1 inch 
in any direction or cracks not wider than 0.02 inch and not longer than 25% of the nominal 



65 



height of the unit are permitted. The specimens produced in the laboratory met this criteria 
and were free of cracks and chips. 

(ASTM C 90 2003) stipulates that units used in exposed wall construction shall not show 
chips, cracks or other imperfections when viewed from a distance of 20 feet under diffused 
lighting. The masonry produced in the research also met this requirement. 

The units produced from waste glass had a finish that had a few exposed glass particles, 
but the majority of the particles were embedded in the paste matrix. The dispersal of the 
glass particles was uniform on all surfaces of the cube produced. The waste glass used in 
the research consisted of various colors of glass including brown, green and clear glass. 
The exposed particles consisting of green glass were visually the most notable. Units 
produced with colored glass might have the potential to produce a very aesthetically 
pleasing surface using know techniques in the field of architectural concrete. A block 
manufacture could experiment with different glass colors and finishing techniques to 
produce a range of appealing block patterns and finishes. 

One concern with the exposed glass particles on the surface of the specimens is whether 
or not they might produce a sharp surface that could be a hazard to the public. Passing 
one's fingers over the surface resulted in no abrasions or cuts to the hand. A photo of the 
cube produced is shown in Figure 5.26. 



66 




Figure 5.26 Photo of CMU Cube with Waste Glass - Top View 

The units produced with rubber tire particles as an aggregate replacement had no exposed 
particles on the surface of the specimen except for the bottom surface. The bottom 
surface in the cube mold may be the hardest to compact during filling of the mold resulting 
in the exposed aggregate. This may be resolved by other compaction methods not used in 
the research such as vibration. Photos of the finished cubes are shown in Figures 5.27 
and 5.28. 



67 




Figure 5.27 Photo of CMU Cube with Rubber Tire Particles - Bottom View 




Figure 5.28 Photo of CMU Cube with Rubber Tire Particles - Side View 



68 



6. Conclusions and Recommendations for Future Research 

6.1 Conclusions 

The usage of recycled waste glass and rubber tire particles in concrete block presents a 
number of possibilities in engineering applications. The results of this study indicate that 
as the amount of recycled material in the mixtures increased, the unit weight decreased. 
The mixtures containing waste glass with replacements rates of 10%, 20% and 30 % had a 
unit weight that decreased 0.8%, 0.9% and 3.4% respectively when compared to the 
control mixture. The mixtures made with crumb rubber showed a more dramatic decrease 
of 3.8%, 5.1% and 7.0% for the same replacement rates. 

This decrease in the unit weight of the concrete block might result in reduced construction 
costs on projects since the units would be lighter to lift and install. Cost savings on wall 
thicknesses and foundation sizes might also occur due to reduced foundation and seismic 
loads from the lighter CMU units. This decrease in the weight of this building material 
could even be more significant if lightweight aggregates were used instead of conventional 
aggregates. 

The results of the absorption testing indicate that the use of waste glass and crumb rubber 
does not significantly affect the durability of the concrete block. Although the absorption 
rate of the samples made with rubber tire particles increased slightly as the rate of 
replacement increased, all of the specimens were well within the acceptable limits of 
(ASTM C 90 2003). 



69 



The strength of the masonry decreased as the amount of waste glass used in the mixture 
increased. The 28 day strength of mixtures with 10%, 20% and 30% waste glass 
replacement rates decreased the compressive strength by 25%, 29.9%, and 32.2% 
respectively. 

Similarly the strength of the masonry decreased as the amount of crumb rubber increased. 
The 28 day strength of mixtures with 10%, 20% and 30% waste glass replacement rates 
decreased the compressive strength of the mixture by 30.7%, 40.3%, and 65.1% 
respectively. The strength reduction for concrete block made with waste glass and crumb 
rubber appear to be slightly higher than comparable concrete mixtures. This may be due 
to the lack cement paste in the zero slump mixture design found in automated block 
production. 

Although the usage of recycled materials affected the strength of the CMU in a negative 
manner, at low replacement rates the concrete block produced may be adequate for 
general masonry construction. At higher replacement rates, their usage might be limited to 
walls that see smaller structural loads such as interior partition walls. 

As the replacement rate was increased there was less of a difference between the 7 and 
28 day strength of the samples. This information might be helpful to block suppliers in 
determining production and delivery schedules for block made with recycled aggregates. 

In reviewing the texture and finish of the CMU samples, the usage of recycled materials did 
not appear to significantly affect the visual appearance or finish of the samples produced. 



70 



The units produced from waste glass had a finish that had a few exposed glass particles 
where as the samples made from crumb rubber had no visual exposed particles except on 
the bottom which might be eliminated by better consolidation. 

The samples met the criteria of (ASTM C 90 2003) for visual appearance and texture for 
exposed applications. They were free of cracks, chips and other defects. 
A few pieces of glass aggregate were visible on the surface of the samples, but the glass 
did not appear to pose a hazard that might cut a person and its presence was small. 

Units produced with colored glass might have the potential to produce a very aesthetically 
pleasing surface using techniques in the field of architectural concrete. This would require 
separation of recycled glass into different colors, but a block manufacture could experiment 
with different glass colors and finishing techniques to produce a range of appealing block 
patterns and finishes. 

There were a number of trash items found in the waste glass as shown in Figure 5.2 such 
as batteries, syringes and other items which might present a health hazard if they are not 
removed from the waste glass. It is recommended that steps be taken to remove all of the 
metal items and consider washing of the waste glass prior to usage in any concrete block 
applications. 

6.2 Recommendations for Future Study 

As discussed in section 2.7.3, concrete made with waste glass in some cases has been 
found by several studies to exhibit the undesirable properties of an alkali-silica reaction 
(Meyer et al. 2001 ). Concrete masonry units are a unique subset of concrete production. 



71 



Due to the manufacturing production parameters required to produce concrete block, CMU 
mixtures have a zero slump requirement. Therefore, CMU mixtures typically have less 
cement paste than other concrete mixtures. It is not known what effect this reduced 
amount of cement paste in CMU mixtures has on alkali-silica reaction. Additional research 
into the effect of ASR needs to be undertaken for this unique concrete product. 

The fire protection capabilities of masonry units made with waste glass and rubber tire 
particles are not well understood at this time. Since one of the goals of research is to 
enable products to be used in the widest possible application, the fire rating of the concrete 
blocks needs to be determined. Building officials will be reluctant to allow usage of the 
building material without documentation of their ability to resist fire damage. 

In addition to the engineering properties reviewed in this paper, other properties need to be 
examined. It is not known if units made with waste glass or rubber tire particles will have 
similar or reduced mortar bond strengths when compared to conventional units. Prism 
testing of units made of waste glass and crumb rubber should be considered. Some 
masonry applications allow for unreinforced walls to be used. Because no reinforcement is 
used in this application, the tensile strength of the unit must be known for a proper 
engineering design. Often masonry is used in shear wall construction to provide lateral 
stability of structural elements. Research into the tensile and shear capacity of units made 
with waste glass and crumb rubber would be helpful in addressing these required 
engineering properties. 

The energy efficiency of a building material can greatly influence the economic viability and 
sustainability of a project. In masonry construction, two thermal properties are often 
considered, thermal mass or the ability of a material to store heat and a material's R value 



72 



or its ability to resist heat transfer. It would be interesting to know if the masonry units 
made with rubber might be beneficial in providing an energy efficient building material. 
Even a slight gain in energy efficiency might result in significant savings in energy costs 
over the life of a building. 

Regardless of the density of a concrete masonry unit, movement control recommendations 
are applicable. Control of cracking and movement is important to the structural integrity 
and aesthetic of a building. (ASTM C 90 2003) requires for acceptable CMU units, the 
linear shrinkage strain shall not exceed 0.065% at the time of delivery. The shrinkage 
testing of the concrete block was not performed in this research, but should be done in 
future work. 

Moisture infiltration through a completed masonry wall is a concern for occupied building 
applications. Walls that allow for excessive moisture penetration can lead to a number of 
unpleasant problems. Although the research above indicated that the absorption of block 
made from waste glass or crumb rubber did not vary significantly from that of the control 
mixture, evaluating the water penetration and leakage of a masonry wall made with waste 
glass or crumb rubber should be performed. 



73 



APPENDIX A: Information on Materials Used in Mixture Designs 

A.1 Materials Used in Research 

The following is information on the materials used in the research. The standards and 
source of materials are shown in Table A.1 . 

Table A.1 Concrete masonry mixture design materials 



Material 


Standard 


Source 


Cement 


ASTMC 150 Type l/l I 


Ashgrove Cement 


Sand 


ASTM C 33 


Bestway Concrete 


Pea Gravel 


ASTM C 33 


Home Depot 


Waste Glass 




Rocky Mountain 
Bottling Company 


Crumb Rubber 




Academy Sports Turf 


Water 




Potable Tap Water 



74 



The chemical composition of the cement used in the research is shown in Table A.2. 



Table A.2 Chemical composition of cement 

Date and Time of Analysis 
Type of Analysis 
Number of Repeats 
Cassette Number 
Type Ml 

Run Average 



Si 
A 1 

Fe 

Ca 

Mg 

S 

Na 

K 

Ci 

L550 

L350 

Total 

NaEQ 

C 3 S 

C 2 S 

C3A 

C 4 AF 

AF 

C0 2 

LSCO2 

LINSTN 

_Pj 



13.54 

4.78 

3.93 

63.55 

1.37 

3.85 

0.243 

0.897 

0.098 

1.00 

2.50 

99.99 

0.83 

56.02 

13.20 

7.01 

10.15 

1.43 

1.5 

35.00 

4.3 

0.00 



7/16/2009 
Concentration Analysis 

1 
43 



Potential alkali reactivity testing of the sand used in the research is shown in Figure A.1 
and a gradation test is shown in Figure A.2 



75 



MSmW 



845 Navajo Street • Denver, CO 80204 



SpeeiMisrsmmi Pmm Imasmv Phone: 303 - 975 " 59 ■ Fax: 303.975.99e9 • to**,,***®****** 

February 26, 2010 



Bestway Concrete 
315 Frontier Court 
Milliken, CO 80543 



Attention: 



Mr. Dan Bentz 



Subject: Laboratory Test Results 

Brighton Pit 

ASTM C 1260 Potential Alkali Reactivity of Aggregates 
ASTM C 33 Fine Aggregate 
ASTM C 33 Coarse Aggregate 
WesTest Project No. 269510 

Gentlemen: 

Enclosed as Figures 1 and 2 are the results of potential alkali reactivity testing (mortar bar 
method), performed on aggregate sampled from the above-referenced source on February 1, 
2010. The aggregate was prepared and tested in general accordance with ASTM Procedures. 
ASTM C 1260 defines the potential of an aggregate for deleterious expansion as follows: 



Test Expansion 


Classification 

Innocuous 

Inconclusive 

Deleterious 


Potential for Deleterious ASR 


<0.10% 

0.10% to 0.20% 

> 0.20% 


Low 

Not Predictable 

High 



Based on the test results of 0.07% and 0.06% expansion at 14 days in solution, 16 days after 
casting, the potential for deleterious alkali-silica behavior of this aggregate in concrete is 
considered low. 

If you have any questions on the data presented, please contact us at your convenience. 



Sincerely, 
WesTest 



Reviewed by: 
WesTest 



Elliot Boyd 



Eric R. West, P.E. 



■■■.' ;- 



76 



SricmisTSTomi Psimb lnousrnr 

045 Navajo Street 

Denver, CO 80204 

303.975.9959 



CLIENT: 
PROJECT NO.: 



Bestway Concrete 
269510 



LABORATORY TEST REPORT 

POTENTIAL ALKALI REACTIVITY OF AGGREGATES 

(MORTAR-BAR METHOD) 

ASTMC1260 



REPORT DATE: February 26, 2010 
SAMPLE ID: Fine Aggregate 



AGGREGATE: 

SOURCE: Brighton Pit 

SIZE: ASTM C 33 Fine Aggregate 

COMMENTS: Aggregate graded as per Section 7.2, Table 1 



SOURCE: Holoim 

TYPE: l/EI GU 

AUTOCLAVE EXPANSION: 0.02% 

ALKALIS CONTENT (as Na equivalent): 0.75% 

COMMENTS: Cement data provided by Holcim 



MIX WATER: 

0.47 w/c ratio 



EFFECTIVE GAUGE LENGTH = 250 mm 




Specimen 


2/11/10 


2/12/10 


2/15/10 


2/19/10 


2/22/10 


2/26'10 


Initial 


Zero 


3 Days 


7 Days 


10 Days 


14 Days 


Comparator 
Reading 


Comparalor 
Reading 


Comparator Length 
Reading Change 


Comparator Length 
Reading Change 


Comparator Length 
Reading Change 


Comparator Length 
Reading Change 

0.095 007% 


A 


-0.232 


-0.068 


-0.050 0.01% 


0.000 003% 


0.044 0.04% 


B 


-0.36B 


0.286 


0.308 0.01% 


0.380 004% 


0.418 0.05% 


0.462 0.07% 


C 


-0.334 


-0.170 


-0.146 0.01% 


-0.088 0.03% 


-0.050 0.05% 


-0.006 0.07% 


AVERAGE 


0.016 


0.037 0.01% 


0.097 0.03% 


0.137 0.05% 


0.184 0.07% 



0.60% 

m 

i 0.50% 

< 
I 

° 0.40% 

O 

z 0.30% — - 

-j 

$ 0.20% ----- 

2 

> 0.10% 



0.00% ®- 



MORTAR BAR EXPANSION 



10 



12 



DAYS IN SOLUTION 



FIGURE 1 



77 



Spicm/srs a ] mi Pimm tmesmr 



845 Navajo Streef 

DBnver, CO 80204 

303975.9959 



CLIENT: 
PROJECT NO.: 



Bestway Concrete 
269510 



LABORATORY TEST REPORT 

POTENTIAL ALKALI REACTIVITY OF AGGREGATES 

(MORTAR-BAR METHOD) 

ASTMC 1260 



REPORT DATE: February 26, 2010 
SAMPLE ID: Coarse Aggregate 



AGGREGATE: 

SOURCE: Brighton Pit 

SIZE: ASTM C 33 Size No. 57/67 Coarse Aggregate 

COMMENTS: Aggregate graded as per Section 7.2, Table 1 



CEMENT: 



SOURCE: Holcim 

TYPE: l/IIGU 

AUTOCLAVE EXPANSION: 0.02% 

ALKALIS CONTENT (as Na equivalent): 0.75% 

COMMENTS: Cement data provided by Holcim 



MIX WATER: 

0.47 w/c ratio 



EFFECTIVE GAUGE LENGTH = 250 mm 


Specimen 


2/11/10 


2/12/10 


2/15/10 


2/13/10 


2/22/10 


2/26/10 


Initial 


Zero 


3 Days 


7 Days 


10 Days 


14 Days 


Comparator 
Reading 


Comparator 
Reading 


Comparator Length 
Reading Change 


Comparator Length 
Reading Change 


Comparator Length 
Reading Change 


Comparator Length 
Reading Change 


A 


-0.434 


-0.280 


-0.270 0.00% 


-0.218 0.02% 


-0.1 BO 0.05% 


-0.128 0.06% 


3 


-1.172 


-1.020 


-1.016 0.00% 


-0.962 0.02% 


-0.90C 0.05% 


-0.S76 006% 


C 


-O.260 


-0.104 


-0.092 0.00% 


-0.042 0.02% 


0.022 0.05% 


0.056 0.06% 


AVERAGE 


-0.468 


-0.45S 0.00% 


-0.407 0.02% 


-0.346 0.05% 


-0.316 0.06% 



0.60% | 
ui 

i 0.50% I- 
< 
z 

u 0.40% -'-- 
z 0.30% ' 



$ 0.20% 



£ 0.10% 
< 



0.00% •- 




MORTAR BAR EXPANSION 



10 



12 



DAYS IN SOLUTION 



FIGURE 2 



Figure A.1 Potential Alkali Reactivity Testing 



78 



UisMst 








LABORATORY TEST REPORT 










Snamisnmtmtimim 

845 Navajo Street 

Denver. CO 60204 

303.975.9959. Fax 303.975,9969 


CLIENT: Bestway Concrete WesTest PROJECT NO.: 269510 
SOURCE: Brighton Plant REPORT DATE: March 2, 2010 
SAMPLED BY: Client 

PROJECT: Brighton Plant Aggregate Testing 


MATERIAL 

DESCRIPTION 


ASTM C 33 Fine Aggregate 


DATE 
SAMPLED 


February 1,2010 


SAMPLE 
LOCATION 


Stockpile 


Aggregate Physical Property and Quality Tests (ASTM C 33, AASHTO M 6 Specifications) 


ASTM C 117 1 C 136, AASHTO T 11 S T 27 


ASTM C 128, AASHTO T 84, 

Bulk Specific Grauity = 2.61, Bulk Specific Gravity 

(SSD) = 2.63, Apparent Specific Gravity = 2.66. 

Absorption = 07% 


ASTM C 88, AASHTO T 104, Sodium Sullate Soundness, 5 Cycles 


SIEVE SIZE 


GRADING 
OF 

ORIGINAL 
SAMPLE 


WEIGHT 
BEFORE TEST, 

S 


PERCENT 

PASSING 

AFTER TEST 


WEIGHTED 
PERCENT LOSS 


SIEVE SIZE 


% Passing 


ASTM C 33 
Spec. 


AASHTO M 

6 Spec, 


1" 








ASTM D 2419, AASHTO T 176 

Sand Equivalent Value = 89 
Specification: 80 Min.(CDOT) 


3/4" 








Minus #100 


4 








1/7 








#50to#10O 


4 








3/o" 


100 


100 


100 


ASTM C 142, AASHTO T 112, Clay Lumps S 

Friable Radicles 

FINE AGG. = 0.0%, Specification: 3.0% Mai. 


# 30 to # 50 


40 


100.0 


0.3 


0,1 


#4 


100 


95-109 


95-100 


#16to#30 


30 


100.0 


0.1 


00 


#8 


98 


80 - 1 00 


80-100 


#8to#16 


20 


100.0 


0.1 


0.0 


#16 


78 


50-85 


50-85 


ASTM C 123, AASHTO T 1 13, Lightweight Particles 
in Aggregate 


#4to#8 


2 


100.0 


0.0 


0.0 


#30 


48 


25-60 


25-60 


3/S" to *f 4 







0.0 


0.0 


#60 


18 


5-30 


10-30 


SAMPLE 
WT. 


LIQUID TYPE/ 
SPECIFIC 
GRAVITY 


LIGHTWEIGHT 
PARTICLES 


SPEC 


TOTAL 


100 


FINE AGG TOTAL 100% 





#100 


4 


0-10 


2-10 


SPECIFICATION: 


10 Max. 


#200 


0.9 


0-3 


0-2 




ZnCI,'2.0 


0.0% 


0.5% Mai. 


ASTM C 40, AASHTO T 21, Organic Impurities: 

Less than Organic Plate No. 1 

Specification: Organic Plate No. 3 or Less 


Fineness Modulus 


2.55 


2.3-3.1 


2.3-3.1 


2146 


ZrE- 2: 


0.0% 


3.0% Man. 


COMMENTS 



Figure A.2 Fine Aggregate Gradation and Soundness Testing 



79 



APPENDIX B: Results Data 

B.1 Phase 1 Results Data 

The reported values in Section 5 of the research are the average of results from three cube 
samples unless noted otherwise. The figures produced in Section 5 connect data points 
and do not attempt any curve fitting of the data. Appendix B contains tables with the actual 
results data of each test specimen tested during the study. Graphs of the results are 
included with data scatter and the best linear curve fitting of the data. The inclusion of this 
information in this appendix is intended to give one a feel of how the results are presented 
in this paper, the scope of the testing performed and the variability of the results. 

The information shown in Table B.1 and Figure B.1 is the data associated with the 
compaction study described in Section 5.6. 

Table B.1 Data for 7 day compressive strength vs. unit weight 



Study 


Sample No. 


Unit 
Weight 
(lb/ft 3 ) 


Strength 
(psi) 


Compaction 
Study 1 


Cube 1 


106.9 


97.5 


Cube 2 


110.6 


102.5 


Cube 3 


108.5 


150 


Average 


108.7 


116.7 


Standard 
Deviation 


1.9 


29.0 


Coefficient of 
Variability 


0.0171 


0.2484 



80 



Compaction 
Study 2 


Cube 1 


116.1 


297.5 


Cube 2 


117.3 


310 


Cube 3 


118.2 


372.5 


Average 


117.2 


326.7 


Standard 
Deviation 


1.1 


40.2 


Coefficient of 
Variability 


0.0090 


0.1230 


Compaction 
Study 3 


Cube 1 


129 


647.5 


Cube 2 


126.1 


622.5 


Average 


127.6 


635.0 


Standard 
Deviation 


2.1 


17.7 


Coefficient of 
Variability 


0.0161 


0.0278 


Compaction 
Study 4 


Cube 1 


129.8 


525 


Cube 2 


128.8 


637.5 


Cube 3 


129.9 


772.5 


Average 


129.5 


645 


Standard 
Deviation 


0.6 


124 


Coefficient of 
Variability 


0.0047 


0.1921 


Compaction 
Study 5 


Cube 1 


128.4 


510 


Cube 2 


132.3 


840 


Cube 3 


129.4 


610 


Average 


130.0 


653 


Standard 
Deviation 


2.0 


169 


Coefficient of 
Variability 


0.0156 


0.2590 



81 



7 Day Strength vs. Unit Weight 



900 



nr- 800 



CO 




a. 








x: 


700 






O) 




o 


600 










U) 




o 


500 


> 




ik 




CO 

'J 


400 


1_ 




Cl 




E 


300 


o 




O 






200 




100 



: -^£ : 



6.0 



5.0 



4.0 



3.0 



2.0 



1.0 



0.0 






C 

o 

o 
> 

CO 

o 

Cl 
E 

o 
o 



100 105 110 115 120 125 130 135 140 

1 Day Unit Weight (lb/ft 3 ) 

Figure B.1 Trendline - 7 Day Compressive Strength vs. Unit Weight 

The information shown in Table B.2 and Figure B.2 is the data associated with the 
absorption testing of the trial mixtures and was used to produce Figure 5.13. 

Table B.2 Data for 7 day and 28 day absorption 



Mixture 


Cube 
1 

(lb/ft 3 ) 


Cube 
2 

(lb/ft 3 ) 


Cube 
3 

(lb/ft 3 ) 


Average 
(lb/ft 3 ) 


Standard 

Deviation 

(lb/ft 3 ) 


Coefficient 

of 
Variability 


7 Day 10% 
Cement 


8.73 


8.33 


9.60 


8.90 


0.65 


0.073 


7 Day 15% 
Cement 


6.57 


6.22 


6.74 


6.51 


0.27 


0.041 


7 Day 20% 
Cement 


7.51 


7.24 


7.33 


7.36 


0.14 


0.019 


7 Day 25% 
Cement 


7.34 


7.00 


7.00 


7.12 


0.20 


0.028 



82 



28 Day 

15% 
Cement 


7.42 


7.59 


7.60 


7.54 


0.10 


0.013 


28 Day 

20% 
Cement 


7.76 


7.59 


7.42 


7.59 


0.17 


0.022 



o 



o 
CO 

< 



10 
9.5 

9 
8.5 

8 
7.5 

7 
6.5 



5 



a 7 Day 



Absoprtion 



; 


i 


i 






: 


; 










; 


; 


i 


i 






- 


\ 


i 


i 
■v 






: 


: 






■ 


1 


~ 


\ 




■ 


1 """^J 


i 

V. A 


i 


\ 




A 
i 


i 
i 


"N. 




\ 




i 


I 




~- 



10 



15 



20 



25 



Percent Cement (%) 
28 Day 7 Day 



Figure B.2 Trendline - 7 Day and 28 Day Absorption 



156.1 



146.1 



136.1 






126.1 £ 



116.1 



106.1 



o 

CO 

< 



96.1 



30 



• 28 Day 



The information shown in Table B.3 and Figure B.3 is the data associated with determining 
the unit weight of the trial mixtures and was used to produce Figure 5.14. 



83 



Table B.3 Data for unit weight of trial mixtures 



Mixture 


Cube 
1 

(lb/ft 3 ) 


Cube 
2 

(lb/ft 3 ) 


Cube 
3 

(lb/ft 3 ) 


Average 
(lb/ft 3 ) 


Standard 

Deviation 

(lb/ft 3 ) 


Coefficient 

of 
Variability 


10% 
Cement 


125.60 


125.17 


124.63 


125.13 


0.49 


0.0039 


15% 
Cement 


130.14 


130.80 


129.30 


130.08 


0.75 


0.0058 


20% 
Cement 


132.80 


134.60 


133.8 


133.73 


0.9 


0.0067 


25% 
Cement 


138.13 


139.10 


136.62 


137.95 


1.25 


0.0091 



Unit Weight vs. Percent Cement 



£ 
£ 



'o 






140 



135 



130 



125 



120 




10 15 20 

Percent Cement (%) 



XL 






Figure B.3 Trendline - Unit Weight of Trial Mixtures 

The information shown in Table B.4 and Figure B.4 are the results of strength testing of 
various mixtures with different water to cement ratios and was used to produce Figure 
5.15. 



84 



Table B.4 Data for compressive strength vs. water to cement ratio - trial mixtures 



Mixture 


Cube 

1 
(psi) 


Cube 

2 
(psi) 


Cube 

3 
(psi) 


Average 
(psi) 


Standard 

Deviation 

(psi) 


Coefficient 

of 
Variability 


10% 

Cement 

Water to 

Cement 

Ratio = 0.8 


640 


665 


693 


666 


26 


0.039 


10% 

Cement 

Water to 

Cement 

Ratio = 0.7 


510 


840 


610 


653 


169 


0.259 


15% 

Cement 

Water to 

Cement 

Ratio = 0.7 


1723 


1435 


1240 


1466 


243 


0.166 


15% 

Cement 

Water to 

Cement 

Ratio = 0.6 


1433 


1815 


2103 


1783 


336 


0.188 


20% 

Cement 

Water to 

Cement 

Ratio = 0.6 


2748 


2310 


2288 


2448 


259 


0.106 


20% 

Cement 

Water to 

Cement 

Ratio = 0.5 


2460 


2968 


4070 


3166 


823 


0.260 



85 



Strength vs Water to Cement Ratio 





4500 




4000 


'co 
a. 


3500 


c 

c 

to 


3000 
2500 


o 
> 

CO 
CO 


2000 


c 

1_ 

E 
o 

o 


1500 
1000 




500 








: <! ; 

: <i — -= z 

^-. i> 

-ir- -=^- 

: JL . 

il 
II 

: II V 



30 



25 



20 



15 



10 



re 
Q. 



c 

c 

1_ 

4— 

to 
o 
> 

CO 
CO 

o 

Cl 

E 
o 

O 



0.4 0.45 0.5 0.55 0.6 0.65 0.7 
Water to Cement Ratio 



0.75 0.8 



10% Cement 
20% Cement 

• 15% Cement 



i 15% Cement 
10% Cement 

- • • 20% Cement 



Figure B.4 Trendline - Compressive Strength vs. Water to Cement Ratio - Trial Mixtures 

The information shown in Table B.5 and Figure B.5 are the results of strength testing of 
several trial mixtures and was used to produce Figure 5.16. 

Table B.5 Data for compressive strength vs. percent cement - trial mixtures 



Mixture 


Cube 

1 
(psi) 


Cube 

2 
(psi) 


Cube 

3 
(psi) 


Average 
(psi) 


Standard 

Deviation 

(psi) 


Coefficient 

of 
Variability 


10% 
Cement 


745 


753 


815 


771 


38 


0.050 


15% 
Cement 


2100 


2390 


1850 


2113 


270 


0.128 


20% 
Cement 


3323 


4215 


3813 


3783 


447 


0.118 



86 



7 Day Strength 



CO 
Cl 



C 

o 

w 
o 
> 

CO 

i_ 

Cl 
E 

o 
o 



4000 



3000 



25.0 




CL 



20.0 £ 



c 
o 



15.0 » 



10.0 



o 
o 



Percent Cement (%) 

Figure B.5 Trendline - Compressive Strength vs. Percent Cement - Trial Mixtures 

B.2 Phase 2 Results Data 

The following is the data results for the phase 2 work. Graphs of the results are included 
with data scatter and the best linear curve fitting of the data unless noted otherwise. 

The information shown in Table B.5 and Table B.6 are the results of thel day unit weight of 
the control mixture and various mixtures with aggregate replacement and was used to 
produce Figure 5.17. Figure B.6 shows the data scatter and trendline of these results. 

Table B.6 Data for 1 day unit weight waste glass replacement 



Mixture 


Control 
Mixture 


10% 
Waste 
Glass 


20% 
Waste 
Glass 


30% 
Waste 
Glass 


Cube 1 (lb/ft 3 ) 


138.78 


137.27 


138.89 


138.67 



87 



Cube 2 (lb/ft 3 ) 


140.62 


139.86 


138.89 


138.89 


Cube 3 (lb/ft 3 ) 


138.24 


139.86 


137.92 


137.59 


Cube 4 (lb/ft 3 ) 


138.78 


138.89 


136.4 


135.43 


Cube 5 (lb/ft 3 ) 


141.59 


138.46 


137.81 


134.78 


Cube 6 (lb/ft 3 ) 


139.54 


136.62 


137.05 


134.46 


Average (lb/ft 3 


135.70 


138.49 


137.83 


136.64 


Standard 
Deviation (lb/ft 3 ) 


1.28 


1.33 


0.99 


1.92 


Coefficient of 
Variability 


0.0092 


0.0096 


0.0072 


0.0146 



Table B.7 Data for 1 day unit weight crumb rubber replacement 



Mixture 


Control 
Mixture 


10% 
Crumb 
Rubber 


20% 
Crumb 
Rubber 


30% 
Crumb 
Rubber 


Cube 1 (lb/ft 3 ) 


138.78 


132.52 


136.19 


131.11 


Cube 2 (lb/ft 3 ) 


140.62 


134.46 


134.68 


129.49 


Cube 3 (lb/ft 3 ) 


138.24 


134.57 


133.81 


131.65 


Cube 4 (lb/ft 3 ) 


138.78 


138.86 


130.25 


128.20 


Cube 5 (lb/ft 3 ) 


141.59 


138.24 


133.06 


128.52 


Cube 6 (lb/ft 3 ) 


139.54 


138.56 


133.16 


126.79 


Average (lb/ft 3 ) 


135.70 


135.70 


133.52 


129.29 


Standard 
Deviation (lb/ft 3 ) 


1.28 


2.68 


1.98 


1.84 


Coefficient of 
Variability 


0.0092 


0.0173 


0.0148 


0.0142 



88 



1 Day Unit Weight 





145 




143 




141 


CO 

3 


139 
137 


-t— ' 
CD 

1 


135 
133 


■4— f 

D 


131 




129 




127 




125 



2,302 




5 10 15 20 25 

Percent of Fine Aggregate Replacement (%) 
* Waste Glass ■ Crumb Rubber 

Waste Glass Crumb Rubber 



C3 



'o 






2,052 



2,002 



Figure B.6 Trendline - 1 Day Unit Weight vs. Percent Aggregate Replacement 

The information shown in Table B.8 and Figure B.7 are the results of the 7 day unit weight 
of the control mixture and various mixtures with aggregate replacement. These results 
were used in Figure 5.18. 

Table B.8 Data for 7 day unit weight 



Mixture 


Cube 
1 

(lb/ft 3 ) 


Cube 
2 

(lb/ft 3 ) 


Cube 
3 

(lb/ft 3 ) 


Average 
(lb/ft 3 ) 


Standard 

Deviation 

(lb/ft 3 ) 


Coefficient 

of 
Variability 


Control 
Mixture 


137.6* 


137.7* 


137.9 


137.7 


0.15 


0.0011 


10% Waste 
Glass 


134.2 


136.2 


139.1 


136.5 


2.46 


0.0180 


20% Waste 
Glass 


136.7* 


137.2* 


136.7* 


136.9 


0.29 


0.0021 



89 



30% Waste 
Glass 


131.6* 


130.9* 


131.3* 


131.3 


0.35 


0.0027 


10% 
Crumb 
Rubber 


130.4 


130.5 


132.3 


131.0 


1.07 


0.0082 


20% 
Crumb 
Rubber 


131.0 


128.8 


129.1 


129.6 


1.19 


0.0092 


30% 
Crumb 
Rubber 


125.0 


129.9 


130.7 


128.5 


3.09 


0.0240 



Asterisk - denotes average result of two sample 



7 Day Unit Weight 



*; 
5 






145 



140 



135 



130 



125 



^ """""- ir- -^ ^ ^ jt 

II ^^^^ 

1111 1 I I I I I I I 1 I I I 1 I I I 1—1— 1—1-1 1 



2302 



2252 



2202 E 



2152 



en 

XL 






I 2102 - 
2052 



2002 



5 10 15 20 25 30 
Percent of Fine Aggregate Replacement (%) 
* Waste Glass ■ Crumb Rubber 
Waste Glass Crumb Rubber 

Figure B.7 Trendline - 7 Day Unit Weight vs. Percent Aggregate Replacement 



90 



The information shown in Table B.9 and Figure B.8 are the results of the absorption tests 
on the control mixture and various mixtures with aggregate replacement and was used to 
produce Figure 5.19. 

Table B.9 Data for absorption vs. percent fine aggregate replacement 



Mixture 


Cube 
1 

(lb/ft 3 ) 


Cube 
2 

(lb/ft 3 ) 


Cube 
3 

(lb/ft 3 ) 


Average 
(lb/ft 3 ) 


Standard 

Deviation 

(lb/ft 3 ) 


Coefficient 

of 
Variability 


Control 
Mixture 


6.74 


7.08 


7.00 


6.94 


0.18 


0.0256 


10% Waste 
Glass 


7.25 


7.17 


6.83 


7.08 


0.22 


0.0315 


20% Waste 
Glass 


7.25 


7.34 


7.34 


7.31 


0.05 


0.0071 


30% Waste 
Glass 


7.08 


7.42 


7.25 


7.25 


0.17 


0.0234 


10% 
Crumb 
Rubber 


7.17 


7.08 


6.66 


6.97 


0.27 


0.0391 


20% 
Crumb 
Rubber 


7.00 


7.51 


7.51 


7.34 


0.29 


0.0401 


30% 
Crumb 
Rubber 


8.33 


7.84 


7.59 


7.92 


0.38 


0.0475 



91 



Absorption 






o 



o 

(/I 

< 



8.5 



7.5 



6.5 



- 










i 


- 










i 

* "^ j 


■ 


, 


^^-^*" 


^,0****^ i 


L-- 




■ 


i 
■ 


i 
1 






i 


- 










: _ 



5 10 15 20 25 

Percent of Fine Aggregate Replacement {%) 

* Waste Glass ■ Crumb Rubber 

Waste Glass Crumb Rubber 



136.1 
131.1 

126.1 
121.1 
116.1 
111.1 
106.1 
101.1 
96.1 



30 






c 
o 



o 

CO 

< 



Figure B.8 Trendline - Absorption vs. Percent Aggregate Replacement 

The information shown in Table B.10 and Figure B.9 are the results of the 7 day strength 
tests on the control mixture and various mixtures with aggregate replacement and was 
used to produce Figure 5.20. 

Table B.10 Data for 7 day strength vs. percent aggregate replacement 



Mixture 


Cube 1 
(psi) 


Cube 2 
(psi) 


Cube 3 
(psi) 


Average 
(psi) 


Standard 

Deviation 

(psi) 


Coefficient 

of 
Variability 


Control 
Mixture 


2170 


2465 


2433 


2356 


162 


0.069 


10% Waste 
Glass 


2405 


2255 


2218 


2293 


99 


0.043 



92 



20% Waste 
Glass 


1973 


1905 


1918 


1932 


36 


0.019 


30% Waste 
Glass 


1700 


1975 


2255 


1977 


278 


0.140 


10% 
Crumb 
Rubber 


1345 


1470 


1705 


1507 


183 


0.121 


20% 
Crumb 
Rubber 


1135 


1353 


1628 


1372 


247 


0.180 


30% 
Crumb 
Rubber 


785 


918 


770 


824 


81 


0.099 



7 Day Strength 



CO 
Q. 



c 

w 

L_ 
-i— 

CO 

o 
> 

'co 

CO 

i_ 

Q. 

E 
o 
O 





- 










-- 














- 


2000 


i__ 


'— — 4 


i 

1 ___ 


^__ 




j. 


- 










— . h 




- 






■ 


i 


a 


1500 
















i 


i 






— 




_ 


■ 


i 


^***^«j 


i 


- 




- 






■ 


i^*^~«^^^ 


- 


1000 












i^,^ 


- 










^"""""--.J 1 


500 


- 










- 


- 










- 


















20 



15 



5 10 15 20 25 
Percent of Fine Aggregate Replacement (%) 
* Waste Glass ■ Crumb Rubber 
Waste Glass Crumb Rubber 



30 



re 
0. 



c 
o 



10 m 



c 
> 

■» 

CO 

c 

Cl 

E 
o 
O 



Figure B.9 Trendline - 7 Day Compressive Strength vs. Percent Aggregate Replacement 



93 



The information shown in Table B.11 and Figure B.10 are the results of the 28 day strength 
tests on the control mixture and various mixtures with aggregate replacement and was 
used to produce Figure 5.21. 

Table B.1 1 Data for 28 day strength vs. percent aggregate replacement 



Mixture 


Cube 1 
(psi) 


Cube 2 
(psi) 


Cube 3 
(psi) 


Average 
(psi) 


Standard 

Deviation 

(psi) 


Coefficient 

of 
Variability 


Control 
Mixture 


2768 


3320 


2880 


2989 


292 


0.098 


10% Waste 
Glass 


2263 


2535 


1930 


2243 


303 


0.135 


20% Waste 
Glass 


1983 


2063 


2238 


2095 


130 


0.062 


30% Waste 
Glass 


1923 


2735 


2128 


2262 


422 


0.187 


10% 
Crumb 
Rubber 


1998 


2280 


1935 


2071 


184 


0.089 


20% 
Crumb 
Rubber 


1843 


1723 


1368 


1645 


247 


0.150 


30% 
Crumb 
Rubber 


1130 


1013 


990 


1044 


75 


0.072 



94 



28 Day Strength 



co 
a. 



c 
o 

w 
o 
> 

to 

CO 

c 

1_ 
Cl 

E 
o 
O 



3500 



3000 



2500 



2000 



1500 



1000 



500 



ll 

: Nv 1""" ~~H : 



5 10 15 20 25 

Percent of Fine Aggregate Replacement (%) 

* Waste Glass ■ Crumb Rubber 

Waste Glass Crumb Rubber 



23.5 



18.5 



13.5 



8.5 



re 
0. 



c 
o 

« 

> 

'co 

CO 

c 



o 
O 



3.5 



30 



Figure B.10 Trendline - 28 Day Compressive Strength vs. Percent Aggregate 
Replacement 



95 



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